While the water from most city treatment plants may be safe when it comes out of the factory, there’s always a real chance it can pick up different kinds of contaminants along the way as it moves in the old pipes.
When you dispense it from your tap, it’s likely to have numerous contaminants like lead, chemicals, and organic compounds which can cause health problems either in the short term or long term.
The good news though is that water filtration technology has advanced to the point that most contaminants that were previously removed by only reverse osmosis systems are now able to be blocked by under sink filters.
Under sink water filters have become more efficient than ever allowing you to take control, minimize and even eliminate the risks posed by the contaminants in the water coming out of your tap.
What is an under-sink water filter?
An under sink water filter is a water purification filter designed to sit underneath the kitchen counter, right underneath the sink itself and it’s connected directly to the under-sink cold water supply where it takes water from and sends it to a filtration media for purification after which it’s sent directly to a faucet for instant dispensing.
What are the benefits?
There are plenty of benefits to using an under sink water filter to purify the water that’s delivered to your sink for drinking or cooking. Here are some of the key ones:
Removes a Wide Range of Contaminants
Unlike the old models which used to use only an activated carbon filter media, modern under sink water filters today combine more technologies that enable them to remove a wide range of harmful contaminants that only the full RO systems could deal with.
The most common contaminant that these filters are very effective at removing chemicals particularly chlorine and chloramines.
They are eliminated by the activated carbon filtration media and most under sink filters at least have one. This media is really good too at getting rid of bad tastes and smells from the water.
Under sink water filters can as well block heavy metals by either using a KDF carbon filter combination or a treated activated carbon filter.
There are also some models that are able to eliminate fluoride and arsenic from the water using a special Alumina filter although this removal is usually not 100% complete.
Nitrite/Nitrate, limescale, sediment, and microorganisms are some of the other impurities that under sink water filters can block from reaching the faucet.
While many RO systems produce wastewater with some even flushing up to 4 gallons of wastewater per day down the drain, under sink water filters don’t generate any wastewater.
It’s connected directly to the under sink cold water pipe and to its own faucet or an existing one, so basically, it produces clean, filtered water without giving out wastewater. Water goes into the filters and leaves through the faucet once purified.
Water on Demand
The other major benefit is that you don’t have to sit and wait for the tank to fill up before being able to dispense water like in the case of an RO filtration system. With an under sink filter, you get clean, filtered water straight from the faucet whenever you need it.
With no additional components such as a storage tank and water pump, under sink filters don’t need much space like RO systems or whole house filtering systems.
In fact, they won’t take one square inch of your countertop space as they go completely under the sink in your kitchen cabinet. Most only require a little space in the cabinet which is convenient if your kitchen is small.
How does an under sink water filter work?
Understanding how an under sink water filter works is essential when you are looking to buy one as it allows you to easily identify the differences between models and builds.
In general, under sink water filters come in two types.
On one hand, we have the simple under sink filters while on the other we have the conventional under sink filters.
The difference between the two types is basically the faucet.
A simple type under sink filter utilizes the existing faucet already installed within the sink unit whereas a conventional type filter will need a faucet of its own which is usually provided alongside the system.
Therefore, how do these filters work?
Well, an under sink water filter basically takes water from your cold water supply under the sink and diverts it to the cartridge where the filtration media stays. Inside the cartridge, the water is passed through the filter media where it’s stripped of different kinds of impurities.
Each model utilizes different variations of filtration media. Some utilize a simple 1-stage process while others feature up to 3 stages of filtration.
However, the most important filtration media in many of under sink water filters is activated carbon. Most filters have at least one which effectively removes chemical contaminants like chlorine, volatile organic compounds (VOCs), and chloramines
Some models utilize two carbon filters, an initial one for trapping most of the chlorine, chemicals, and larger contaminants and a second one to ensure the remaining chemical contaminants are cleared out from the water.
The most advanced units incorporate UV light sterilizer to thoroughly clean the water and there even models equipped with a remineralization filter to provide filtered alkaline water.
Once the water is sufficiently purified by the filter, it’s sent out to the faucet on the sink where it’s dispensed for consumption. The process happens on-demand, so no wastewater is generated and it works completely by water pressure.
For a simple under sink filter, the water will be delivered through your regular faucet. You will only have one cold water faucet and one hot water faucet if you have it installed. Only the water from your cold water line gets filtered not the hot water.
For a conventional filter, once the water is filtered, it’s directed to a dedicated faucet mounted on the sink. This faucet is independent of your regular kitchen faucets for cold and hot water, and you have to install it.
Therefore, you get to still use the two regular faucets separately and benefit from the filtered water from the unit for cooking or drinking. Installation and Maintenance
Under Sink Water Filter Installation
Installation of under sink filtration systems is usually easy and straightforward. The filter is installed inside the cabinet underneath your kitchen sink.
You may, however, be required to drill a hole on the sink if you are installing a conventional under sink filter to accommodate the faucet it comes with. This is if you don’t already have one spare hole.
The following procedure is for setting up a conventional under sink water filter and can be used for the installation of simple under sink filters too without the drilling part.
First, drill a ½” hole on the spot you want to mount the faucet using a masonry drill bit.
Insert the faucet and secure it into the hole while ensuring it’s properly aligned in the right spot. (Check our RO system installation article for detailed steps for installing an RO faucet)
Once the faucet is installed, turn off the cold water supply under the sink and drain the water inside the line.
Mark the location where you want to place the filter inside the under sink cabinet.
Screw the filter into the mounting location and perform all the necessary plumbing connections. Most models will have a mounting bracket to allow you easily attach the filter to the cabinet wall.
Install the fitting to your cold water supply line and connect the tubing from the under sink water filter to the fitting and then to the newly installed faucet.
For the simple under sink filter type, there’s no separate dispenser, so simply connect the filter directly to your cold water line and the existing cold water faucet.
Test the new filter to see all the connections are good and then leave the filtered water to run for about 5 minutes before using it.
Every model will come with its own installation procedure. You should ensure to follow the manufacturer’s instructions manual to prevent encountering any difficulties.
Under Sink Water Filter Maintenance
Like any other water filtration system, an under sink water filter requires regular maintenance which involves cleaning and changing the filter cartridges after a certain time scale depending on your usage and quality of your incoming water.
There’s no general timeline on when to change the filters as their lifespan will vary from one different brand to another.
However, most models require changing once every 6 months. There are several models that can last up to 1 year while a few others can go for up to 5 years before requiring replacement.
Below is a basic process for replacing an under sink water filter cartridge although it may vary based on the model you have:
Turn off the cold water supply and open the faucet to drain all the water in the system
Using a screwdriver, housing wrench, or the tool provided by the manufacturer, open the casing and remove the filters.
Nicely clean the casing and then insert the new filter, and close the casing well.
Once everything is set, turn on the water and check for leaks. If there are none, let the water run for 5 minutes before you use it.
NOTE: All the filters should be replaced at the same time even if some look better than others to ensure the system performs efficiently.
Advantages and Disadvantages of Under Sink Water Filters
As much as under sink water filters have nice qualities, we believe it’s good to also be aware of all the pros and cons of these products so that you remain critical when making your final decision.
Advantages of Under Sink Water Filters
Effectively improves the water quality
Whatever contaminants you are concerned about, there’s an under sink water filter that can deal with them. You can select the filter according to the type of contaminants you are more concerned about.
Makes the water taste and smell much better – all under sink water filters often have an activated carbon filter which eliminates most of the chemicals and unpleasant odors hence improving the taste of the water and making it more pleasant to drink.
Filtered water on-demand
There’s no waiting for water to dispense with an under sink filter as the water is delivered instantly unlike in RO systems. You just turn on the faucet and get clean filtered water instantly.
Save countertop space
Under sink filters are usually much compact in size and they don’t need a lot of space inside the cabinet. It not only leaves enough room to store other items but you also get to save your precious countertop space.
Easy installation and low maintenance
Setting up an under sink water filter unit requires minimum capabilities. You don’t need any special skills and there several simple DIY videos throughout the internet to show the process. Changing the filter elements after a certain period is also the only maintenance you will have to do.
The purchase price of these filters is not high compared to basic RO systems. Plus the maintenance cost is low too since the replacement filters are affordable and usually last a long time, so you save a good amount of money in the long run since you don’t have to replace the filters as often.
A variety of options to choose from
There is a wide range of under sink water filters out there to meet the needs of each user depending on the kind of contaminants you want to remove.
There are standard models and even more advanced options with several filtration stages to deal with stubborn and persistent contaminants.
Disadvantages of Under Sink Water Filters
May need a separate faucet
Conventional under sink water filters utilize their own faucet provided by the manufacturer. This faucet is independent of your regular kitchen faucets and requires installation hence you may have to cut an extra hole into your sink.
Depends completely on water pressure
Under sink water filters work completely using the source water pressure. Therefore, any drop in the water pressure going into the unit will certainly lower the rate of filtration and production of purified water at the faucet.
An under sink water filter provides a convenient and much 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 which 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.