The Best Under Sink Water Filter System

The specific type of under sink water filter system that is best will depend on the contaminants present in the water, the desired level of filtration, and the amount of water needed to be filtered.

In this article, we’ll explore the different types of under-sink water filter systems available and help you choose the best one for your specific needs.

So, keep reading to learn more and take the first step towards cleaner, safer, and better-tasting water right from your kitchen sink.

Types of under sink water filter systems

There are several types of under-sink water filter systems to choose from, each with its own unique set of advantages and disadvantages.

Single-stage under sink water filter

The first type of under-sink water filter system is the single-stage filter.

This is the most basic type of system and typically consists of a single filter cartridge that removes sediment and other impurities from the water.

While single-stage filters are relatively inexpensive, they may not be as effective as multi-stage filters or reverse osmosis systems.

A single-stage under sink water filter system is the simplest type of under sink water filter.

As the name suggests, it uses only one filter cartridge to remove contaminants from the water.

The filter cartridge typically contains a carbon filter or a sediment filter, or both.

A carbon filter removes chlorine, bad taste, and odor from the water, while a sediment filter removes larger particles like sand and rust.

Single-stage under sink water filters are generally the most affordable option and require the least maintenance.

They are ideal for those who have relatively clean water but want to improve the taste and odor of their drinking water.

However, they may not be effective in removing all contaminants, especially those that require multiple stages of filtration.

If you have serious water quality issues, a single-stage filter may not be sufficient to address them.

It’s important to note that not all single-stage filters are created equal.

The quality of the filter cartridge and the filtration technology used can vary greatly between different brands and models.

It’s important to choose a reputable brand that uses high-quality materials and filtration technology.

Multi-stage under sink water filters

Multi-stage filters are more advanced than single-stage filters and typically consist of several filter cartridges.

The systems remove a wide range of impurities from the water.

In addition to sediment and other particles, multi-stage filters can remove chlorine, heavy metals, and other contaminants.

Some multi-stage filters also include a UV sterilizer that kills bacteria and viruses.

Multi-stage under sink water filter systems are designed to remove a wide range of contaminants and impurities from water.

They typically use a combination of different filters to achieve this.

The first stage of a multi-stage under sink water filter system usually consists of a sediment filter.

This filter is designed to remove large particles like sand, rust, and dirt from the water.

It prevents these particles from clogging up the other filters in the system, prolonging the life of the other filters.

The second stage of a multi-stage under sink water filter system is typically an activated carbon filter.

This filter is designed to remove chlorine, pesticides, herbicides, and other chemicals from the water.

It can also remove bad tastes and odors, making the water more pleasant to drink.

Some multi-stage under sink water filter systems may also include additional stages, such as a second activated carbon filter, a KDF filter to remove heavy metals, or a ceramic filter to remove bacteria and viruses.

Overall, multi-stage under sink water filter systems are an excellent choice for those looking for a comprehensive water filtration solution.

They are highly effective at removing a wide range of contaminants and can improve the taste and odor of your water.

Under sink RO system

Reverse osmosis (RO) systems are the most advanced type of under-sink water filter system.

These systems use a semi-permeable membrane to remove a wide range of contaminants from the water, including bacteria, viruses, and dissolved solids.

RO systems typically include several pre-filters that remove sediment and other particles before the water reaches the membrane.

While RO systems are more expensive than other types of under-sink water filter systems, they are also the most effective at removing contaminants.

Under-sink reverse osmosis (RO) water filter systems are a type of under-sink water filter that uses a multi-stage process to remove impurities from water.

RO systems use a semipermeable membrane to filter out contaminants, including minerals, chemicals, and bacteria.

The RO system typically includes a pre-filter to remove sediment, a carbon filter to remove chlorine and other chemicals, and a semipermeable membrane to filter out smaller particles.

Some systems may also include additional stages, such as a post-filter to remove any remaining impurities and a UV sterilizer to kill any remaining bacteria.

RO systems are highly effective at removing a wide range of contaminants, including heavy metals, dissolved solids, and fluoride.

They also improve the taste and odor of water, making it more pleasant to drink.

One drawback of RO systems is that they can waste a lot of water during the filtration process.

For every gallon of purified water produced, some systems may use up to four gallons of water.

However, some newer systems are designed to be more water-efficient.

Overall, RO systems are a good choice for those looking for highly effective filtration and purification of their drinking water.

However, they may be more expensive and require more maintenance than other types of under-sink water filter systems.

The benefits

Using an under sink water filter system has many benefits for homeowners who want to improve the quality and taste of their drinking water.

Here are some of the top benefits of using an under sink water filter system:

Improved water quality

Under sink water filter systems are designed to remove contaminants and impurities from your tap water, providing you with clean and safe drinking water.

Cost-Effective

Under sink water filter systems are more cost-effective than bottled water or other filtration systems that require frequent replacements of filters or cartridges.

Convenient

Under sink water filter systems are installed directly under the sink, so they don’t take up much space and are out of sight. They are also easy to maintain and change filters when needed.

Better Taste

Removing impurities and contaminants from your tap water can improve the taste and odor of the water, making it more enjoyable to drink.

Environmentally friendly

Using an under sink water filter system can help reduce plastic waste associated with bottled water.

Health benefits

Drinking clean and safe water can help improve overall health and reduce the risk of waterborne illnesses and diseases.

Versatility

Under sink water filter systems can be customized to fit the specific needs of your household, such as removing specific contaminants or minerals.

The downside

Although under sink water filter systems provide many benefits, there are some downsides to consider:

Installation

Under sink water filter systems require installation, which may be difficult for those without plumbing experience.

Professional installation is recommended, which can increase the cost.

Maintenance

Under sink water filter systems require regular maintenance, including filter replacements and cleaning.

Neglecting maintenance can lead to decreased performance or even system failure.

Space

Under sink water filter systems take up space in your cabinet, which may be a concern for those with limited storage space.

Cost

Under sink water filter systems can be more expensive than other types of water filters, especially if professional installation is required.

Limited water flow

Some under sink water filter systems may have a lower water flow rate, which can be an issue for those who need large amounts of water quickly.

Wastewater

RO under sink water filter systems produce a significant amount of wastewater, which can be wasteful and increase your water bill.

It’s important to weigh these downsides against the benefits of an under sink water filter system to determine if it’s the right choice for you.

Buying guide

Under sink water filter systems are a great option for anyone who wants a convenient and effective way to purify their drinking water.

They are especially useful for those who want an out-of-sight filtration system that doesn’t take up counter space or require frequent maintenance.

Additionally, under sink water filter systems are ideal for individuals who want to filter large volumes of water and have a dedicated filtration system for their drinking water.

This is particularly beneficial for those who live in areas with poor water quality or have concerns about contaminants in their water.

Furthermore, under sink water filter systems are a good choice for homeowners who prefer a permanent filtration solution, as opposed to portable or countertop filters that need to be replaced frequently.

With proper maintenance and filter replacement, under sink water filter systems can provide high-quality drinking water for years.

Overall, under sink water filter systems are a versatile and practical option for anyone who wants to ensure the safety and quality of their drinking water.

However, it’s important to consider individual needs and preferences when selecting a water filtration system, as different types of filters may be better suited for certain situations.

When choosing the best under-sink water filter system for your home, it’s important to consider your specific needs and budget.

Single-stage filters are a good option for those on a tight budget, while multi-stage filters are a good balance between affordability and effectiveness.

If you’re concerned about the quality of your water and want the best possible filtration, an RO system may be the best choice for you.

here’s a buying guide to help a user choose the best under sink water filter system for their home:

Water quality testing: Start by getting your water tested to determine what type of contaminants are present in your water.

This will help you choose the right type of under sink water filter system that can effectively remove those contaminants.

Types of filter systems

Decide which type of under sink water filter system is best for your needs – single stage, multi-stage, or RO.

Each system has its own advantages and disadvantages, so it’s important to consider your specific needs before making a decision.

Water flow rate:

Check the water flow rate of the under sink water filter system you’re considering.

The flow rate should be sufficient to meet your household’s needs without compromising the filtration quality.

Filter replacement frequency and cost: Look into the replacement frequency and cost of the filters for the system you’re interested in.

You’ll want to choose a system that is cost-effective and has filters that are easy to replace.

Installation

Consider how easy it is to install the under sink water filter system.

If you’re not confident in your DIY skills, you may want to choose a system that comes with professional installation.

Maintenance

Consider the maintenance required for the under sink water filter system.

Some systems require more maintenance than others, so choose one that fits your lifestyle and schedule.

Certification

Look for under sink water filter systems that are certified by organizations such as NSF International, Water Quality Association, or Underwriters Laboratories.

This ensures that the system has been independently tested and certified for performance and safety.

By following these guidelines, you can choose the best under sink water filter system for your household’s needs, ensuring that you have clean and safe drinking water.

Best under sink water filter systems

Below are our in-depth reviews of the best under sink water filter systems that we believe really stand out in terms of performance, efficiency, capacity, reliability, and overall quality.

If you are thinking of getting an under sink water filter, then these are the best models you should consider.

You will find sufficient information about these must-have devices regarding what they are, how exactly they work, their main purpose, and their benefits.

CuZn UC-200

The CuZn UC-200 is one of the best top-rated under sink water filters on the market. What makes it highly popular is its impressive filtration features, advanced design, quality, super efficiency, and convenience all at a relatively fair price. More importantly, it has the most long-lasting filter offering the highest capacity on our list.

Filtration Performance

The CuZn UC-200 model utilizes a 3-stage filtration process which consists of a micro sediment membrane, KDF-55 filtration media, and virgin acid-washed catalytic carbon filtration media made from coconut shell carbon.

This impressive filtration process and advanced materials remove a wide range of contaminants from your water both inorganic and organic.

The first media which is the micro sediment membrane helps clear out sediments and tiny particles from the water.

The KDF-55 media and catalytic coconut shell carbon combination, on the other hand, work effectively to remove many different kinds of harmful chemical contaminants found in the water and the pipes.

The first main items they eliminate are chlorine, chloramines, and chlorine byproducts like chloromethanes and bromoform.

The robust catalytic coconut shell carbon filtration media is also capable of reducing most types of pharmaceutical and perfluorinated (PFOA) compounds.

It can reduce Glyphosate too and several volatile organic compounds found in municipal water. 

In short, it will basically remove almost all chemical contaminants that often affect the taste, odor, and quality of water.

The UC-200 KDF-55 filtration media stage, in particular, does a great job of reducing up to 98% of all the water-soluble cation heavy metals like lead, chromium, nickel, mercury, cadmium, and other dissolved metals.

Another commendable thing about this unit’s filtration process is that it purifies the water selectively.

It will not remove the beneficial hardness minerals such as calcium and magnesium.

Therefore, you get clean filtered water with healthy minerals present.

Bacteriostatic Filtration System

One of the best features of the CuZn UC-200 model is its bacterial growth prevention.

It is bacteriostatic which means bacteria can’t grow within the unit as is the case with carbon-only filters which are susceptible to the building up of microorganisms over time when not changed frequently.

The inclusion of the KDF-55 media helps create a bacteriostatic environment in the unit which limits any possibility of microorganism growth and also kills any bacteria present in the water.

By direct electrochemical contact and flash formation of hydrogen peroxide and hydroxyl radicals, this KDF redox media causes cellular damage to the microorganism lingering inside the unit by disrupting their ability to function thereby destroying them completely.

As such, there’s almost zero chance of bacteria, mold, and algae building up within the system thereby preventing any further contamination of the water and the potential spread of water-borne diseases.

Capacity and Efficiency

The CuZn UC-200 offers an incredibly high capacity as it is able to filter a maximum of 50,000 gallons of water on demand throughout its lifespan.

Basically, you will be using it for nearly 5 years or even longer if it’s only for drinking water and cooking.

The unit is also built to withstand a great deal of pressure. It’s capable of handling up to 130 psi operating pressure which is a big bonus considering that the city water pressure in most homes is around 60 psi.

The flow rate is equally high as the system can produce about 2 gallons of filtered water per minute and the best part is no wastewater is generated in the process, so it’s 100% water efficient.

Installation and Maintenance

Installing this CuZn system is super easy.

All the necessary parts required to hook it up under your home or office sink are provided.

The unit is designed to filter cold water from municipal/city water treatment supplies alone.

It’s not recommended for use with private well water suppliers. 

A separate dedicated faucet for filtered water is not required since it can work with an existing cold water faucet.

However, if you prefer to install it, the manufacturer provides a complementary alternative installation kit for the dedicated filtered water faucet setup upon request at no additional cost.

Almost no maintenance is needed because the filter it uses is long-lasting.

You will only have to change the system after around 5 years and the process is simple as the first time you install it.

One downside we noted with this unit is that it does not consistently reduce a high percentage of fluoride.

It reduces the levels by just 20 to 30% on average.

It’s also not the right choice for dealing with excessively hard water issues brought about by extremely high mineral content since most of these minerals are allowed to pass through the filter.

Overall, this CuZn UC-200 model is a top under sink water filter that offers reliable general purification of municipal water issues.

If you want a more basic yet effective low maintenance and long-lasting water filtration system, then this is an option worth investing in.

Pros

• Removes a wide range of organic and inorganic contaminants
• Kills and restricts the growth of bacteria and mold within the system
• Incredibly high capacity (50,000 gallons) and flow rate (2 GPM)
• 100% efficient with zero wastewater generation
• Setting it up is a breeze and almost no maintenance needed
• Long-lasting filter offering up to 5 years of service
• Comes with a 5-year limited warranty

Cons

• The “in” and “out” flow not indicated on the unit
• Filters only municipal water

Woder WD-S-8K-DC

The Woder WD-S-8K-DC, just like the CuZn-200 above is really popular under sink water filters and this is mainly due to its simplicity and effective filtration ability.

The other thing that makes it very attractive to many is the large capacity it has, in fact, it’s the second-highest on this list.

If you are looking for a compact unit that can give you good value for your money, then this may be the best choice for you.

Filtration Performance

Although quite small, this powerful water filter is extremely capable of reducing a huge percentage of contaminants that water treatment facilities fail to remove as well as those picked up along the way.

The filtration media the system uses is a special blend of granulated carbon and silver that have been grounded to microparticles, screened, and then blended together rather than layered.

This filter design provides a large surface area hence ensuring optimum contact time with the water which extremely boosts the absorption ability of the filter making it super effective at extracting contaminants from the water.

It will be able to remove 99.99% of chlorine and lead plus many more other contaminants like VOCs, carcinogens, chloramine, as well as heavy metals such as mercury and chromium 6.

It will filter out turbidity too and get rid of that unpleasant odor and taste often caused by most of the chemical contaminants in the water. In addition to that, the Woder 8K is bacteriostatic, so it will prevent the growth of bacteria, mold, or any other microorganisms within the filter.

Its special blend of media also gives it a selective filtration ability which clears out harmful impurities but keeps all the essential minerals that are vital to our health, including calcium, magnesium, and potassium.

Therefore, you and the family will get to enjoy healthy and great-tasting purified water.

Capacity and Efficiency

This Woder WD-S-8K-DC is an under-sink water filter with a large capacity as it can process up to 8, 480 gallons of water before needing a change of filter which is the second-highest capacity on this list.

It means it can last more than 3 years with normal use hence it’s ideal for long-term use.

If you are not a fan of changing filters frequently, this will fit you right. 

Regarding the flow rate, the filter will deliver around 2 gallons of water a minute at 65 psi which is the average rate of most under sink filters. The best part is the fact that it uses microparticles means that it will be able to remain optimally effective while purifying your water for those 3 years.

However, this will only be possible if you make sure you use it with municipally treated cold water alone or at least disinfected water, not well water.

Installation and Maintenance

With its simple and compact design, the installation process of the Woder 8K is easy and straightforward.

It shouldn’t take more than 5 minutes.

The package features all the parts you need including the direct connect hoses.

You just mount it where you want and connect it directly to your 3/8” cold water line under the sink and the existing standard cold water valve faucet.

You don’t need a separate dedicated faucet to dispense filtered water.

Low maintenance is another advantage you will get from this filter since it can for about 3 years before requiring changing and it has a built-in valve to allow you to perform the replacement without turning off the water.

You will have to replace the whole thing though.

To sum it all, Woder WD-S-8K-DC is a very capable under-sink water filter that will give you amazing value for your money, especially because of its high capacity.

It’s a suitable choice for city water and its construction feels solid and strong, so you are assured durability.

Pros

• Effective filtration process that’ll remove 99% of contaminants
• Eliminates bad odor better and prevents microorganisms build-up
• Uses selective filtration technology which keeps essential minerals
• Relatively high capacity that can serve you for more than 3 years
• Easy to install and requires low maintenance
• Comes with a 1-year limited warranty

Cons

• Does not remove fluoride
• May reduce water pressure a bit

APEC WFS-1000

APEC is a reputable manufacturer of water filtration systems with a long history of producing quality products.

Their WFS-1000 under sink water filter system does not disappoint either as it’s amongst their top products with much positive reception. 

It’s a basic under sink water filter designed purposely for removing chemical contaminants from the water, especially chlorine.

If your water is already good but you just want to refine it and protect yourself against any potential contamination, then this is a nice option to check out.

Filtration Performance

The WFS-1000 has 3 filtration stages consisting of a sediment filter and two carbon block filters which together provide a commendable filtration performance.

At the 1st stage is the high-grade 10″ polypropylene sediment filter which extracts as many sediments as possible from the water including dust, rust, silt, and other tiny and major particles in order to protect and maintain the filtering ability of the next stages.

The water then goes through an extruded carbon block filter in the 2nd stage which is typically made up of activated carbon particles fused together into a single block.

This serves as the first point of carbon filtration where a majority of the chlorine, VOCs, and other chemical contaminants like pharmaceuticals, pesticides, and herbicides are initially removed from the water.

Unwanted tastes, odors, cloudiness, and residual sediments are cleared out as well at this stage.

The 3rd stage has the same extruded carbon filter which performs the final refining by further removing the remaining chlorine, odor, tastes, color, cloudiness, and other chemicals.

The use of these dual carbon filters significantly boosts the filtration performance of the unit allowing it to get rid of almost all the chlorine, tastes, and VOCs from the water, and also organic chemicals.

The mineral composition and alkalinity of the water do not change throughout the filtration process.

The result is mineral-rich water that’s clean, looks clear, and tastes fresh.

Capacity and Efficiency

APEC has not specified the total gallon rating for this WFS-1000 model but if we have to give an estimate, it will process more than 1,000 gallons of water before needing replacement.  

For a lot of households with regular normal usage, this means it’s likely to last 1 to 2 years provided your water is not highly contaminated.

It’s a decent lifespan compared to most similar systems.

Although the unit uses three filtration stages, you won’t notice a big change in the water flow. It has a maximum flow rate of 1.6 gallons per minute, thereby it will filter the water quickly and provide a continuous on-demand supply of clean purified water to your faucet. Furthermore, no water is wasted, so your monthly water cost won’t change much.

Installation and Maintenance

The WFS-1000 comes fully assembled for installation. What’s required is to mount it in the desired location, insert the filter cartridges, and connect the tubing.

The challenging part may be to install the faucet as it’s designed to work with a separate dedicated faucet for dispensing filtered water.

The package comes with a 100% lead-free chrome faucet, hence if there’s no pre-made hole in your kitchen counter, you might have to drill one to install this faucet.

The unit falls in the medium to large size end and as such, it should fit under most standard kitchen cabinets.

If it’s small, then you will have to adjust some stuff to create room for it.  

There’s little work to do with regard to maintenance because it’s just replacing the filters at least after every 12 months and it’s equally an easy and quick process.

Now one of the setbacks of this unit is that despite having dual activated carbon filters, it still cannot eliminate chloramine from water which might be a concern for those living in cities that utilize chloramine to treat water instead of chlorine.

According to APEC, the filter will also not remove fluoride, bacteria, and heavy metals like lead and arsenic.

Total dissolved solids as well pass right through the filters.

What this generally means is that it’s not ideal at all for filtering well water.

In conclusion, as long as you are seeking to purify only municipal water that’s treated with chlorine, the APEC WFS-1000 will be a better fit for you.

It will serve you for a long and deliver the water quality you desire.

Pros

• Designed for removal of sediments and chemical contaminants
• Eliminates unpleasant tastes, odors and water cloudiness
• Doesn’t interfere with essential minerals or water alkalinity
• Can process more than 1,000 gallons of water before replacement
• Installation is fairly easy as well as changing the filters
• Comes with a 1-year limited warranty and a dedicated standard faucet

Cons

• It’s not able to filter out chloramine, fluoride and heavy metals
• Not the most compact under sink water filter system

APEC CS-2500

Our next under sink water filter is the APEC CS-2500 water filtration system.

This is a strong but more basic under sink water filter from APEC built to provide dependable filtration at an affordable price.

It’s a good starting point for those who are looking for a simple, budget under sink filter for improving the quality of their city water.

Filtration Performance

The APEC CS-2500 filtration process relies purely on a single filter cartridge for the removal of several different kinds of contaminants commonly found in water supplied from municipal treatment plants.

It utilizes a carbon block filter which may seem like a standard carbon filter but it does offer a respectable contaminant rejection rate.

This highly porous medium is able to eliminate up to 97% of chlorine, bad tastes, odors, and various other chemicals such as herbicides and pesticides from the water.

The media is also capable of removing 90% of all lead plus other heavy metals while ensuring that essential minerals like calcium and potassium remain in the water.

It’s a much ideal filter for dealing with lead or anything chemical that contaminates your water.

Besides that, it’s designed to be bacteriostatic and as such, it will as well remove heterotrophic bacteria and inhibit them from growing or reproducing within the unit which is a big plus in preventing any possibility of further contamination happening inside the filter.

Capacity and Efficiency

Like the APEC WFS-1000, the exact filtration capacity of this APEC CS-2500 model has not been clearly specified but according to APEC, its maximum contaminant reduction capacity is around 5,000 gallons and that should allow the filter to go for up to 12 months before you can change it.

The water flow rate is 1.67 gallons per minute which are good enough to ensure you get filtered water on-demand quickly plus you won’t notice any drop in water pressure when using the filter.

Installation and Maintenance

The best part of this unit aside from its filtration ability is that it offers a trouble-free installation.

Using the provided standard 3/8” connector, you screw in the inlet line from the filter directly to your cold water supply valve and then screw in the outlet line to your existing faucet stem.

It’s that easy and you don’t require a separate faucet.

The lines will handle pressures of up to 125 psi thanks to the twist connection design and they are likely to leak under high pressure compared to push-in hoses.

This quick twist connection design also enables easy filter replacement which you won’t have to do more frequently as the filter cartridge lasts up to 12 months without changing out.

The lifespan may vary though depending on the quality of water going into the unit.

Generally, there’s little to worry about this under-sink water filter.

It’s a basic and economical water filtration system suitable for removing chlorine, heavy metals, and a few other contaminants from treated municipal water.

Due to its compact size as well as easy installation, it can be a perfect choice for RV owners.

Pros

• Removes a good number of contaminants
• Destroys and prevents bacterial build-up
• Essential minerals remain in the filtered water
•  Decent flow rate and filter lifespan
• Easy to install and to replace the filter cartridge

Cons

• Does not remove fluoride
• Cannot be used with well water

iSpring US31

Taking the 7th spot on our list is the iSpring US31 under sink water filtration system.

iSpring is a famous company in the water filtration industry known for producing top-of-the-line water filtration systems particularly reverse osmosis systems and replacement parts.

The company now includes under sink water filters on its long list of products and the US31 is one of its best models that has made a significant mark on the market.

It has been built to the same level of quality we’ve seen in most of iSpring’s systems with an aim to provide a convenient and efficient way to facilitate the supply of clean, healthy water.

Filtration Performance

To start, the US31 filter system features a more standard design with 3 separate stages of filtration that work to remove a lot of harmful contaminants.

In the 1st stage, the water flows through a universal 10” polypropylene sediment filter where common sediments are cleared out down to 5 microns.

It removes sand, dust, rust, dirt, and all tiny particles which not only improves the purity of water but also helps protect and extend the life of the system itself.

The 2nd stage contains a 5-micron CTO carbon and GAC filter which is a combination that effectively removes chlorine, chloramine VOCs, and many more common chemicals that contaminate the water and cause colors, cloudiness, bad tastes, and odors.

These two filters also help reduce the number of heavy metals like lead and arsenic present in the water.

From there, the water goes through another CTO carbon filter in the 3rd stage where the remaining chlorine, chloramine, VOCs, and other chemicals, as well as heavy metals, are further extracted from the water thereby improving its taste, smell, and clarity.

These three stages will remove all these contaminants without losing the minerals in the water as is the case with RO systems.

The filter is equally designed to control and discourage bacteria and parasites from developing in the water, thereby if bacterial contamination is of concern, then you are guaranteed that the filtered water produced at the faucet will be of great quality.

Capacity and Efficiency

This US31 model from iSpring is rated to provide up to 2000 gallons of water which is sufficient capacity to give you almost one year of service before you can replace the filter cartridges.

Basically, depending on the usage and water quality, you will have to change the filter cartridges every 6 to 12 months.

The higher the usage and level of contamination, the shorter the lifespan will be.

The flow rate, on the other hand, can reach up to 1 gallon per minute again depending on your source water pressure. 

It may not be that high, but it’s just fast enough to ensure you constantly have access to clean water on demand straight from your tap.

Installation and Maintenance

Installing and maintaining the US31 is a somewhat simple task although you may have to drill an extra hole into your countertop since it uses a separate faucet included in the kit.

If you are handy or have some basic DIY skills, it could take less than 30 minutes to set it up and the kit has everything you need including the feed water adapter, tubes, fittings adapter, a wrench, and a clear and easy-to-follow installation manual.

All three filter cartridges require replacing every 6 to 12 months and as we mentioned above, this will depend on your usage and the level of contamination of your water.

Changing the filter is as easy as installing them the first time and even much better, the 1st stage filter has a clear see-through housing to enable an easier visual inspection of the cartridge so that you can always replace it at the right time.

Moreover, the system can handle a maximum pressure of 90 psi, so the fittings are not going to blow apart and come out with the standard 60 psi municipal water pressure.

Considering that the 3-stage filtration process is highly effective in removing different contaminants and the capacity is reasonably large, the iSpring US31 is a unit that we would recommend to anyone looking for quality and reliability.

Pros

• Will effectively remove sediment, chlorine, and several different contaminants
• Keeps essential minerals and prevents bacteria from thriving in the water
• Relatively high capacity of up to 2,000 gallons of water
• Simple DIY installation and maintenance process
• Has a clear see-through 1st stage housing for an easy visible inspection
• Comes with a durable, brushed nickel all-metal dedicated faucet
• Backed by a 1-year limited warranty

Cons

• The flow rate is a bit low at 1 GPM
• Meant for use with only municipal water

Aquasana AQ-5200

Aquasana is another reputable brand that continues to enjoy a lot of popularity in the water filtration business and they are well known for their eco-friendly filtering options.

Their AQ-5200 is amongst the top performing under sink water filter systems on the market and the main reason behind this is the fact it’s one of the few models that have the most contaminant certifications.

Here is an outlook of its major highlights and setbacks.

Filtration Performance

The AQ-5200 utilizes Aquasana’s panted and NSF certified Claryum filtration technology which is a 2-stage high-performance filtration process designed to remove over 60 common water contaminants.

In fact, it’s only a tiny handful of filters on the market that use this filtration technology which consists of activated carbon media, catalytic carbon filter media, and ion exchange.

The activated carbon filtration adsorbs organic chemicals in the water such as VOCs, MTB, herbicides, and pesticides as well as pharmaceuticals like ibuprofen and estrone.

From there, the water goes through a catalytic carbon filter where it isolates and eliminates chlorine and chloramines thereby improving the taste and color of the water.

The next filtration phase involves an Ion exchange which takes care of heavy metals like mercury, lead, and arsenic.

The system is also equipped with absolute sub-micron mechanical filtration (ASMF) which helps capture asbestos plus chlorine-resistant cysts such as giardia and cryptosporidium.

The use of these different filtration technologies significantly enhances the unit’s performance compared to its competitors allowing it to remove over 97% of the contaminants in the water.

In addition to this, the AQ-5200 is certified as well to remove PFPA and PFOS, and the filtration process itself is selective hence retaining the naturally beneficial minerals resulting in filtered water that’s cleaner, healthy, and tastes great.

Capacity and Efficiency

Filtration capacity is the area where the AQ-5200 slightly falls short because it’s only capable of processing up to 500 gallons of water before requiring changing.

This is the lowest capacity on our list, but if you use the filter to process around 2 to 3 gallons every day, it will likely last up to 6 months which is fairly good.

Water flow rate is another area that this unit doesn’t really do well in as it can deliver just 0.5 gallons per minute.

This only translates to a 25% increase in the flow rate compared to a normal tap and as such, you may experience a slightly slow pour but the unit is efficient.

No water is wasted and the unit can handle a maximum working pressure of 80 psi and a minimum working pressure of 20 psi.

Installation and Maintenance

You will need no plumber to set up this AQ-5200 system if you are a handy person because it’s designed for easy DIY installation with everything you require to get the job done included in the package.

It comes with a separate dedicated faucet, so you will have to do some drilling if you don’t already have an extra mounting hole drilled into your sink.

Changing the filters is a snap too. No disconnecting hoses or water lines.

All it takes is a simple twist to unscrew the filter housing, remove the old cartridge and insert the new one.

You only toss the filter cartridge and keep the housing which makes the replacement a bit less costly considering that the filter lasts up to 6 months.

The amazing thing about this Aquasana unit is that it’s fitted with a performance indicator which is a smart-tech system that will show the efficiency of the filter and notify you when the filter requires to be changed.

Therefore, no need to keep checking or guessing when to replace the old filters which is a big plus in terms of ensuring the system remains effective throughout in filtering out contaminants.

To sum it all up, while the capacity and flow rate are on the lower end, the AQ-5200 is solid under a sink water filter system with reliable filtration technology.

The low capacity may be a deal-breaker for some but if your regular water usage is not that high and you want a unit with great filtration power that will deliver healthy clean water, then this is an option you can absolutely consider.

Pros

• Removes over 60 different contaminants
• Retains the naturally beneficial minerals
• Installation and filter replacement is easy
• Alerts you when it’s time for replacing the filters
• Comes with a 1-year warranty and a 90-day guarantee

Cons

• Water flow is slower than most other filters
• Low filtration capacity at 500 gallons
• Suitable for only water with adequate disinfection like municipal water

Aquasana AQ-5300+

The Aquasana AQ-5300+ also known as 5300 Max Flow is much similar to the Aquasana AQ-5300 model but with a slightly larger capacity and faster flow rate.

However, the two models feature 3 filtration stages rather than the 2-stage process of the AQ-5200 model.

In other words, the AQ-5300+ is a robust and super-effective system as you are going to see below.

Filtration Performance

Like the AQ-5200 above, the Aquasana AQ-5300+ model utilizes Claryum filtration technology but with an additional stage to make it a 3-stage filtration system.

Stage 1 of the system is fitted with a 20-micron sediment pre-filter which traps silt, dirt, rust, and other visible sediments to prevent the following stages from clogging too quickly.

It’s a feature that often misses in most under sink water filters yet it’s really essential, particularly in areas where the sediment and silt levels in the water are higher than normal.

Stages 2 and 3 consist of Aquasana’s Claryum filtration technology which is made up of an activated carbon filter, catalytic carbon filter, ion exchange, and sub-micron filter.

At first, the water flows through the granular activated carbon filter where a significant amount of both organic and inorganic chemical contaminants that include chlorine herbicides, pesticides, pharmaceuticals, and VOCs are removed from it along with unpleasant tastes and odor caused by these chemicals.

From there, the water goes through the catalytic carbon filtration media which is a more powerful carbon filter that clears out 99% of the chlorine and remaining chemical contaminants in the water. It also totally reduces chloramine present in the water, something that most under sink water filters cannot.

After that, the water passes through an Ion exchange filter which features a series of resin beads with a large surface area and they work effectively to extract heavy metals like mercury and lead plus other micropollutants that the carbon filters fail to catch.

At the last stage of the filtration process which is the 3rd stage, we have the sub-micron filter which clears out the remaining particles and contaminants from the water down to 0.35 microns.

It will capture asbestos, chlorine-resistant cysts like cryptosporidium and giardia, and any other impurities that the earlier two stages couldn’t remove.

These three stages together will eliminate up to 99% of 77 different kinds of contaminants but leave behind healthy minerals to give you clean, fresh, and natural-tasting water.

They will also not remove other total dissolved solids (TDS) and the only microbes they can remove are cysts hence it’s not that effective for bacterial removal which simply means you should only use the unit to filter treated water that’s microbiologically safe.

It’s certainly not recommended for use with well water which doesn’t contain chlorine for disinfection.

Capacity and Efficiency

While the AQ-5200 has a filtration capacity of 500 gallons and the AQ-5300 600 gallons, this AQ-5300+ model offers up to 800 gallons before a change of filters is needed. 

This slight improvement in the total amount of water it can process is mainly brought about by the larger cartridges it uses and it will allow you to utilize the unit for up to 6 to 8 months before replacing the filters.

The flow rate is equally a bit faster than that of the previous two models.

They delivered not more than 0.5 gallons per minute yet the AQ-5300+ provides 0.72 GPM which is not much change but it’s significant enough to ensure you get slightly faster water flow from the faucet.

Installation and Maintenance

Hooking up this Aquasana unit should not pose a problem if you have some basic DIY skills.

The installation manual explains the entire process step by step and all the necessary parts are included with the first set of filters already installed in the system.

It won’t take more than an hour to set it up but like the AQ-5200, it comes with its own dedicated faucet that you need to install, so some drilling might be involved.

Not much maintenance is required other than occasionally changing the filters at least after every 6 months and cleaning the exterior of the unit.

Another good thing is that this system too comes with a battery-operated alarm/indicator which will beep an audible alert and flash red to remind you when filter replacement is needed.

You can even link the system to your phone via Bluetooth to receive the alerts on your phone.

There’s an app from the manufacturer that you can download and install for free, and keep track of the number of gallons of water that have been processed. 

Unfortunately, this app is only available for iOS devices.

The indicator also uses a battery that will require changing with every filter replacement which translates to some additional costs although not very much to cause concern.

From all these wonderful features to the high filtration performance, it’s safe to say that the Aquasana AQ-5300+ is an under-sink water filter that’s worth every penny.

For those that prefer Aquasana products and the AQ-5200 model didn’t win them over, this is an alternative you might want to check out.

Pros

• Highly effective filtration process for an under sink water filter
• Removes 99% of chlorine and chloramines, and keeps essential minerals
• Decent filtration capacity of up to 800 gallons
• Fairly easy DIY installation and filter replacement
• Monitors filter life and alert you when filter replacement is needed
• Can be linked to a phone via Bluetooth for easy filter life monitoring
• Comes with a 2-year warranty and a 90-day satisfaction guarantee

Cons

• The water flow rate is somewhat low at 0.72 GPM
• Does not remove fluoride or treat bacterial contamination

Culligan US-EZ-4

The US-EZ-4 is one of the three models in Culligan’s US-EZ series with the others being the US-EZ-1 and US-EZ-3.

Among the three, the Culligan US-EZ-4 stands out the most due to its high filtration performance.

This and several other nice features you are going to see are what earn it a spot on our list of the best under-sink water filters.

Filtration Performance

Although it’s just a single-stage filter system, this Culligan US-EZ-4 model is equipped with a super-effective filter cartridge which is more than capable of getting rid of most of the common contaminants and impurities found in water.

It offers almost the same level of filtration ability as any other top 2-stage or 3-stage under sink water filter system.

The unit utilizes a 0.5-micron high-tech carbon block filter media which has been tested by NSF International and certified to NSF/ANSI standard 42 as well as standard 53.

These certifications first mean a significant reduction of chlorine in the water.

It will clear out up to 97% of chlorine along with bad tastes, odor, and turbidity, and will remove nominal particulate class 1 which includes all particles that are as small as 0.5 microns.

Unlike the US-EZ-3 and US-EZ-1, the US-EZ-4 will also eliminate chloramines from your water which is really commendable for a one-stage unit.

Most under sink water filter systems have standard carbon filters that only filter out chlorine but will not remove the very persistent chloramine disinfectant used by municipal water treatment plants.

Besides that, this filter will remove other harmful chemical contaminants like MTBE, dozens of VOCs, and perfluorinated chemicals such as PFOA and PFOS.

The US-EZ-4 can as well remove cysts like giardia and cryptosporidium plus lead, mercury, and several other heavy metals. On average, it will reduce up to 99% of lead in the water.

As you can see, while it’s not a 3-stage system, it’s still a highly effective filter that can address many common contamination issues found in municipal water supplies.

Furthermore, it does leave behind some of the healthy, natural minerals in the water hence the water delivered to the faucet is clean and has good taste.

Capacity and Efficiency

When it comes to capacity, the US-EZ-4 falls on the lower end like the Aquasana AQ-5200 above.

It can process up to 500 gallons of water which is just about average and means it will work for around 6 months depending on your usage. However, if you use not more than 2 gallons a day, it can go up to 8 months.

The flow rate is on the lower end too as it delivers 0.5 gallons per minute at 60 psi, but again if your daily water usage is not so high, then the 0.5 GPM should be good for you.

Installation and Maintenance

With a detailed DIY instruction manual and quick connect fittings, installing this unit will be somewhat easy and everything required for setup is provided.

The challenging part may be installing the dedicated chrome faucet it comes with if you don’t have a pre-drilled mounting hole as you will need to drill one.

Filter replacement is a hassle-free process since the filter head features the convenient twist on/off mechanism which allows you to change the filter cartridge within seconds without even turning off your feedwater supply.

This mechanism also prevents the mess that usually happens when changing out traditional filters. 

There’s an LED filter life indicator on the faucet that automatically monitors the filter life and produces an audible sound to notify you when it’s time for filter replacement which is yet another convenient feature that simplifies the maintenance of the unit.

The connections are made of good quality plastic material and once tighten properly, they will not leak and can handle water pressures of up to 80 psi.

In general, the low filtration capacity and flow rate are the only things that may be of concern for some people, but in terms of performance and build quality, it doesn’t disappoint.

For an inexpensive and effective one-stage under sink water filter, this Culligan US-EZ-4 model is a superb deal especially if you are on a tight budget.

Pros

• Effectively removes most common water contaminants
• Healthy minerals are not filtered out from the water
• Simple to set up and replace the filter cartridge
• LED filter life indicator ensures timely filter replacement
• Backed by a 2-year limited warranty

Cons

• Average filtration capacity rating at only 500 gallons
• 0.5 GPM flow rate is a bit slower than other basic models

Filtrete Maximum (3US-MAX-S01)

In the 12th position is the Filtrete Maximum 3US-MAX-S01 model which is the most economical pick on this list and one of the few wonderful water filters on the market that’s priced at that low.  

The unit is part of three models under Filtrete’s 3US series with the other two being the Standard (3US-AS01) and Advanced (3US-PF01) water filters. 

The major difference between these three models is their filtration capacity but the Filtrete 3US-MAX-S01 which we are going to look at below stands out in terms of getting rid of contaminants as it provides the highest rate of filtration.

It’s cheaper and definitely more dependable than the other two models.

Filtration Performance

The Filtrete Maximum 3US-MAX-S01 is a simple 1-stage system featuring a high-capacity filter media that has received both the NSF 42 and the much more stringent NSF 53 certifications.

This means it’s very capable of significantly enhancing the quality of your municipal water.

The system utilizes a 0.5-micron carbon block filtration medium which is way more effective compared to basic carbon-based filters with the ability to remove 97% of chlorine taste and odor alongside other select chemicals like the pesticide toxaphene, herbicide atrazine, and select pharmaceuticals.

It has the additional capability of clearing out lead and microbial cysts (giardia and cryptosporidium) by over 90%.

The filter is also able to trap sand, dirt, rust, and other particulates present in your water down to 0.5 microns which is a huge plus because a lot of other carbon filters can only reduce particles that are as small as 5 microns.

The fact that it meets the NSF 53 certification means that it’s relatively sufficient to remove VOCs and other heavy metals although not to a large extent. 

From our own assessment, we would say that this is a system that’s more geared towards dealing with heavily chlorinated water and lead, and several common city water issues as well.

It’s not a unit for use with well water.

Capacity and Efficiency

We mentioned earlier that filtration capacity is the major factor that differentiates the three models in Filtrete’s 3US series.

Both Standard (3US-AS01) and Advanced (3US-PF01) water filters provide a maximum of 2,000 gallons of filtration capacity.

As for this Filtrete Maximum 3US-MAX-S01 model, it’s rated to process up to 1,500 gallons of water before it requires to be changed.

It’s a little lower than its counterparts but still, it’s on the higher end when you put it side to side with the other contenders herein.

Even so, Filtrete recommends a 6 months replacement cycle which makes it no different from the other picks with lower capacity.

Apart from the large capacity, this unit will deliver water at a rate of around 1.5 gallons per minute.

That’s faster than what many competing sing-filter systems can offer.

It’s more than adequate to cater to the needs of those with regular high water usage.

Installation and Maintenance

Installing the system, it’s an easy DIY process with only a single filter to mount inside your under sink cabinet where it will fit nicely without taking up so much space.

It’s extremely compact and it works with any standard kitchen faucet, so drilling is needed.

Maintaining this system is easy too.

You just have a single filter cartridge to replace which should be done twice a year.

One weak point we noted though is that the unit utilizes a simple push-in design to connect the tubing to the plumbing instead of a secure compression fitting.

Therefore, the connections may possibly not be that secure and can lead to leaks in case of very high pressure.

The fittings plus the faucet are made from plastic and hence are also not as sturdier as the other picks that use metal.

All in all, being a low-cost under sink water filter that pretty much does its job well, the Filtrete Maximum 3US-MAX-S01 is definitely a convenient option for those that don’t want to break the bank.

It will save you money and provide the necessary filtration performance to keep your tap water clean and safe.

Pros

• Effective at reducing chlorine, lead, and other common contaminants
• Large capacity at 1,500 gallons and faster water flow at 1.5 GPM
• Simple DIY installation as well as filter cartridge replacement
• Takes up little space and works with the existing kitchen faucet
• Highly affordable with multiple grades of replacement filters to choose from

Cons

• The fittings and faucet are all plastic
• Not rated for filtering well water

GE GX1S50R Under Sink Water Filter

The GE GX1S50R is a small, simple under sink water filter but packs a commendable punch as far as removing contaminants in the water is concerned.

It’s an excellent choice for reducing chlorine and undesirable particles from lowly-contaminated municipal water.

Filtration Performance

Water entering the GE GX1S50R system from the cold water supply goes through a single-stage filtration process inside the filter cartridge where several different kinds of contaminants are extracted from it.

The system uses a high-quality activated carbon filtration media which removes up to 97.6% of chlorine, and negative tastes and odors.

This medium is also able to clear out 99% of lead and filterable cysts like giardia and cryptosporidium.

The other contaminants it will remove from your water include turbidity, asbestos, lindane, atrazine, and heavy metals like mercury.

If your water often comes out with small particles suspended in it, then this General Electric filter will as well come in very handy.

Alongside removing most of the chemical contaminants, it’s capable of trapping nominal particulates down to 0.5 microns which clears out 98.8% of dirt, rust, sediment, sand, silt, and any other particulate present in the water.

It’s basically a dependable and reliable single-stage filtration that can supply fresh, filtered water but only for use with already treated water like from city treatment plants.

We wouldn’t recommend it at all for filtering well water.

Filter Capacity and Efficiency

The GE GX1S50R filter cartridge can process a maximum of 750 gallons of water before it can be replaced. It’s a low-capacity unit but if you are processing 4 gallons of water a day, then it can work effectively for up to 6 months.

 Water comes out of the faucet at a maximum flow rate of 0.75 gallons per minute which again is not that high but will do fine for low-demand usage.

Installation and Maintenance

You can successfully install this unit with some basic DIY skills.

It uses a separate dedicated chrome faucet which will require drilling a mounting hole into your countertop but once you are done with that, the rest is straightforward.

The filtration system is a single filter unit with a small footprint, so it will fit anywhere, even in tight spaces.

The filter head features a twist and lock design that makes replacing the filter cartridge equally fast and easy.

You will have to change it at least twice a year and to save you from guesswork, General Motors has integrated a filter life indicator with a reminder light on its dedicated faucet.

It will conveniently remind you when it’s time to replace the filter cartridge to maintain the best filtration results.

Overall, if you need a water filtration system purposely for filtering out chlorine, lead, and unpleasant tastes and odor, then you may consider getting this GE GX1S50R under sink water filter.

Pros

• Good for removing chlorine taste and odor
• Can trap nominal particulates down to 0.5 microns
• Average filtration capacity of 750 gallons
• Easy to install and has low maintenance
• The faucet features a filter life indicator
• Comes with a 1-year limited warranty

Cons

• Shorter filter life and low filtration rate
• Not recommended for filtering well water

Whirlpool WHAMBS5

The Whirlpool WHAMBS5 is the last model on our list but certainly not the least.

Coming from a company that has been in the industry for the longest time, this model is a quality yet budget-friendly under sink water filter system that provides the necessary filtration capability to keep your municipal water clean and safe for your family’s daily usage.

Filtration Performance

The Whirlpool WHAMBS5 utilizes a 3-stage filtration process that’s certified to NSF/ANSI standards 42 and 53 to remove numerous harmful and undesirable elements in tap water.

The 1st stage is a standard 10” sediment filter cartridge with a specialized design meant to trap incredibly tiny sediments and particles from the water

It will clear out rust, dirt, silt, and other particulates down to 0.5 microns thereby preventing the filter cartridges in the following two stages from clogging.

The 2nd stage consists of a standard 10” carbon block filter cartridge which removes up to 99% of lead in the water and as well serves as the pre-filter to the 3rd stage by reducing a good amount of chemical contaminants that cause unpleasant odor and taste.

The 3rd stage features a much bigger filter cartridge compared to the other two stages and it’s the heart of the system.

It holds a larger top-quality activated carbon block filtration medium that provides a higher surface area than standard carbon-based filters.

The larger surface area significantly enhances its adsorption ability allowing it to effectively eliminate greater amounts of chlorine (up to 97%) and many other chemical contaminants such as benzene, pharmaceuticals, pesticides, insecticides, herbicides, and industrial solvents.

It will also clear out all the bad odors and tastes caused by these chemicals. 

Moreover, this large activated carbon filter conforms to the NSF Protocol P231 for the reduction of microbiological contaminants.

Therefore, it will equally serve as a microbiological purifying filter with the capability of removing at least 99% of bacteria, microbial cysts, and viruses.

The three stages will remove all the above contaminants and much more but at the same time, it will leave the natural essential minerals found in the water giving you healthy, great-tasting purified water.

Filter Capacity and Efficiency

Whirlpool has rated this model to process a maximum of 550 gallons throughout its lifespan which puts it in the same category as the other low-capacity models we’ve reviewed.

Provided you process around 2 to 4 gallons of water per day, you can expect to receive 4 to 6 months of reliable filtration performance before you replace it with a new filter cartridge.

The water flow rate stands at a maximum of 0.74 gallons per minute, so also expect a moderate delivery speed, a little bit slower than that of your regular cold water kitchen faucet.

Installation and Maintenance

The Whirlpool WHAMBS5 system comes with a dedicated filtered water faucet that needs to be mounted on your countertop.

If you have an available faucet hole, you will have an easier time setting up the entire system, otherwise, you will need to drill one which is the only tricky part, especially for first-timers.

The unit holding the three cartridges is compact and will fit neatly in any standard-sized under sink kitchen cabinet.

You won’t break a sweat either when it comes to replacing the filter cartridges since they use a twist-in design.

It requires just a simple ¼ turn to release the old filter, then pulls it out and replaces it with the new one. 

You don’t need to turn off the water supply plus the faucet is equipped with an amber LED indicator that monitors the filter life after installation.

It will flash continuously once the 6 months have passed to alert you that the filter cartridges and battery need changing hence saving you from getting caught off guard. 

Though the filtration capacity and water flow rate leave a lot to be desired, we can comfortably say this Whirlpool WHAMBS5 model is a very decent and well-made under-sink water filter system.

It’s a nice budget option for those who wish to enjoy safer, better-tasting water without making a big dent in their wallet. 

Pros

• A rigorous filtration process removes numerous contaminants
• Capable of removing microbiological contaminants like bacteria and viruses
• Won’t interfere with the natural essential minerals in the water
• Installation is relatively simple while filter replacement is a breeze
• The faucet has an amber LED indicator that alerts when to change the filters
• Backed by a 1-year limited manufacturer warranty

Cons

• Filtration capacity is low at only 550 gallons
• The speed of water flow is low too at 0.74 GPM

Conclusion

An under sink water filter provides a convenient and affordable way of getting an instant supply of clean and healthy water.

They are best for purifying municipal water with fairly low levels of contamination which doesn’t require an RO system to remove.

The above-mentioned models have impressive filtration performance and can address various kinds of common tap water issues.

However, your choice will depend on the particular contaminants you want to remove from your water as well as the capacity.

You should go for a high-capacity system that has a faster flow rate and a long-lasting filter that is easy to replace.

CuZn UC-200 and Woder WD-S-8K-DC models are some good examples.

All in all, whatever unit you pick, make sure to confirm that it’s certified and capable of removing the contaminants that are often present in your water and require minimal maintenance.

We’re certain that with our reviews above, you will find it easier to make an informed decision and pick the best model for your household.