Best Under Sink Water Filters

Under sink water filtration systems are an affordable and effective way to provide clean, purified water without sacrificing space in your kitchen or signing up for high ongoing running costs.

As the name suggests, under sink water filter systems sit within the kitchen unit below the sink and are connected to the incoming water supply.  The filter unit is connected to the faucet (or to an additional faucet installed next to the sink) and delivers filtered water whenever the faucet is used. 

Unlike Reverse Osmosis systems there is no waste water generated and under sink filter units are available with a range of different filter cartridges to ensure that the unit you choose can effectively treat any impurities in your area.

Top 10 Under Sink Water Filtration Systems

IMAGE PRODUCT FEATURES
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    Cost: $$
    Filter Life: 6 months
    Flow Rate: 0.25GPM
    Filter Type: Carbon
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    Cost: $$
    Filter Life: 6 months
    Flow Rate: 0.5GPM
    Filter Type: Claryumo
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    Cost: $$
    Filter Life: 3 years
    Flow Rate: 2GPM
    Filter Type: Microparticle
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    Cost: $
    Filter Life: 6-12 months
    Flow Rate: 1GPM
    Filter Type: Carbon
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    Cost: $
    Filter Life: 6-12 months
    Flow Rate: 1GPM
    Filter Type: Ceramic
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    Cost: $$$
    Filter Life: 5 years
    Flow Rate: 2GPM
    Filter Type: KDF & Carbon
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    Cost: $
    Filter Life: 6 months
    Flow Rate: 0.5GPM
    Filter Type: Carbon
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    Cost: $$
    Filter Life: 12 months
    Flow Rate: 0.5GPM
    Filter Type: Carbon
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hd-table__image

    Cost: $
    Filter Life: 6 months
    Flow Rate: 0.5GPM
    Filter Type: Carbon
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    Cost: $
    Filter Life: 6 months
    Flow Rate: 2.25GPM
    Filter Type: Carbon
CHECK PRICE

Best Under Sink Water Filter Reviews (2020 Update)

 

1. Ecosoft 3-stage High Capacity

Ecosoft’s 3-stage tankless under counter water filter was a real surprise for us and snuck in for the top spot in our review.

3-stage filtration removes heavy metals, chlorine, sediment, and reduces manganese and iron levels too.  The Ecosoft filters scale-causing minerals magnesium and calcium, softening the incoming water too.

With a faucet included and standard filter life of 6 months, this under sink filtration system was faring well in our comparisons until we discovered the price… and realized you can pick one up on Amazon for less than $100, with replacement filters available for less than $20!

Everything you need for installation comes in the box and fitting is simple enough for most competent people to carry out themselves in under an hour.

Although the low flow rate is a drawback, we don’t think you’ll find a better all-round package for this price.

Pros

  • Affordable setup kit and filters 
  • Faucet included
  • Easy installation
  • Did we mention these are affordable?!

Cons

  • Lower flow rate

 

2. Aquasana AQ5300 3-Stage Under Sink Water Filter

This 3-stage filtration system from Aquasana has all of the features you’d expect from an under sink filter, at a truly affordable price. 

Filters are expected to last 6 months and can be changed without needing any tools and the unit’s installation itself is similarly simple, being a straight-forward exercise for a competent DIYer.

The system will filter chlorine, heavy metals, organic compounds and pesticides while maintaining a flow rate of 0.5 GPM through the stylish faucet that is included in the box.

This is one of the budget choices we included on our list. Despite its cheap price, this water filter is capable of producing clean and crisp water, just like the more expensive models. The faucet is also available in a range of finishes so you can be sure it will fit into your existing décor.

Pros

  • Tool-free filter change
  • Good flow rate

Cons

  • Some wear items (such as seals and o-rings) will not last as long as competing models

3. Woder 5K-Gen 3-DC

The 5K from Woder is a basic model in terms of its features but what it lacks in imagination it makes up for in quality.

Removing 99.99% of contaminants including heavy metals, lead, chlorine and pesticides, the 5k filter connects directly to your existing faucet using the included hoses.

The expected filter life is up to 3 years, far longer than most on the market, and the mightily impressive flow rate of 2 GPM is one of the highest we have seen from any under sink water filter.

Installation is very simple requiring only an adjustable wrench and less than an hour.

Pros

  • High flow rate
  • Long filter life
  • Affordable

Cons

  • Some reports of metallic taste even after flushing

4. iSpring US31

With 2 carbon block filters and a sediment filter as well, this 3-stage filter will prevent all but the very smallest particles reaching your faucet.  Chlorine, pesticides and heavy metals are all reduced in the water supply.

Install of the iSpring US31 is very straight forward without needing specialist tools and the pack includes a faucet, saving you from having to adapt your existing tap connections (although you have the option to connect to the existing tap if you prefer).

The filters in this unit should need replacing only once every 6-12 months and the compact design means the US31 will fit comfortably in most kitchen sink units.

Although the iSpring US31 doesn’t actively soften the water, we rate this as a solid offering that will perform, and last well for many buyers.

Pros

  • Faucet included
  • Easy installation
  • Can be used wih existing tap

Cons

  • Low flow compared to other filters

5. Doulton W9330958 Supercarb

The Doulton Supercarb filter has been designed with space-saving in mind.

With new faucet included and its slim-line filter, Doulton have produced an under sink filter designed to be as convenient as possible, whilst still offering 4 stage filtration at a competitive price.

The unit will filter chlorine, bacteria, sediments and parasites, and the filter body has an antimicrobial coating to maintain hygiene and reduce the likelihood of bacterial growth contamination during periods when the filter is not in use.

The unit is very simple to install and has excellent filtration however the low flow rate means it is not ideal for a family home, where more water is preferable.

Pros

  • Excellent filtration
  • Well-made and robust

Cons

  • Low flow rate
  • Some plumbing parts needed to install

6. CuZn UC-200 Under Counter Water Filter

With an average 4.8 star rating from almost 1,500 Amazon reviews, it would be fair to say that the UC-200 is a popular under sink water filter… 91% of reviews rate it as five star!

Connecting directly to your existing faucet, this unit has a filter rated to last for 5 years – by far the longest lasting filter on our list.

The UC-200 doesn’t actively soften water and is unsuitable for use with well water, but it provides outstanding results when used with municipal water supplies.  The unit inhibits bacterial and mold growth whilst providing excellent filtration of chlorine, pesticides, heavy metals, sediment, algae and bad tastes and odors.

Easy to install, the unit doesn’t require the installation of an additional faucet and requires virtually no maintenance.

The only downside is the unit’s size, which is quite bulky although still small enough to fit within your existing kitchen cupboard unit.

Pros

  • Excellent filtration
  • Very long filter life
  • Responsive customer support

Cons

  • Larger than other under sink filter units

7. Watts Premier WP-2-Stage

The Watts Premier WP500313 is a 2-Stage under counter filtration unit, capable of reducing bacteria, lead, sediments, VOCs and herbicides from the incoming water supply.

A faucet is included in the box with the filter and installation can be completed in less than an hour without needing the assistance (or cost) of a plumber.

The flow rate and water pressure are both relatively unaffected by fitting this filter and Amazon buyers report that the filtered water is great to drink and the unit comfortably fits below your kitchen sink, although there are some concerns over the product’s longevity and tendency to leak after having been installed for several years.

Pros

  • Quality filtered water
  • Easy installation
  • Faucet included

Cons

  • Questions over longevity of filter casing

8. Brondell H2O+ Coral UC300

One of the more popular 3 stage filtration systems, the UC300 offers effective purification for less than $100 without compromising flow rate.

Filters are expected to last up to 12 months and they are designed for quick replacement without the need for tools. 

The UC300 includes a smart stainless steel faucet for the filtered water feed and is Gold Seal Certified by the Water Quality Association.

This filtration system reduced heavy metals, pesticides and VOCs as well as improving bad tastes and odors, and its small footprint means you won’t have to dedicate a whole cupboard to the system.

Pros

  • Long filter life
  • Compact filter design saves space

Cons

  • Additional plumbing fittings needed for most installations
  • Awkward to fit

9. Amazon Basics AMZN-PB-1DCS4M114M

This budget filter from Amazon is an effective budget under sink filter however Amazon’s lack of expertise in this area shows when compared to some of the other filters in our test from more established manufacturers.

Water pressure at the faucet is reduced once the filter is installed and replacement filters are surprisingly hard to find. 

The filter does provide effective filtration, and at a very low price we are sure that there will be plenty of buyers however we would recommend investing a few extra dollars in an under sink water filter from a brand with industry expertise.

Pros

  • Easy installation
  • Affordable

Cons

  • Doesn’t soften water
  • Unknown technical support

10. Filtrete Advanced Undersink Filter

Although this under sink filter from Filtrete is a budget model, it is remarkably effective at filtering out contaminants and will be an excellent choice for anyone considering installing an under sink filtration system without making a large investment. This filter demonstrates the benefits of these systems at a fraction of the cost of some competitors’ filters

No faucet is included with this filtration system, so the filtered water line is piped directly to your existing cold tap, meaning that all filtered drawn through the faucet is filtered.

Installation is very simple and the filters are expected to last up to 6 months – the standard for these systems.

Chlorine, sediments, rust and microbial cysts are all removed or reduced in the water supply and although filtration of heavy metals and pesticides is not prioritized, we suspect that when Filtrete designed this model they were looking to provide the most improvement in water quality for the lowest price.

Pros

  • Very competetive price
  • Effective filtration

Cons

  • Does not filter heavy metals
  • No seperate faucet included

Under Sink Water Filter Buyer’s Guide

As with most water filtration products, it can be easy to get washed away in a flood of technical jargon and confusing comparisons.

Our guide aims to simplify these handy systems so that you know what’s important and what’s not, and give you the tools to decide which is the best under counter water filter for your home.

Lucky for you, we’re here to help.

What to Look For When Selecting an Under Sink Water Filter

Water pressure

Water pressure and flow rate are often overlooked when choosing an under sink filter however they will be one of the most important factors in product satisfaction once you have purchased a filter… if it takes a minute to fill a small glass of water you will soon regret the decision.

This is usually a question of balance – as the water is being forced through the filters some pressure and flow will be lost however the faster the water moves through the fewer contaminants are prevented from reaching the faucet.

Type of Filter and Contaminants Removed

The type of filter used in your under sink water filter will affect the contaminants which the filter can remove from the drinking water supply, its longevity and the cost of replacement filters.

Most under sink filters use a combination of activated carbon filters and pre-filters to trap sediments and organic materials within the incoming water supply. Filters or casings can be bacteriostatic or are often given an antimicrobial coating to prevent mold and bacteria growth within the filter.

UV filtration and KDF filters are usually used in some models. To learn more about types of water filter, click here [link to other article]

 

Cartridge Longevity and Cost of Filter Replacements

Cartridge longevity will determine how regularly the filters need to be changed, while the cost of replacements is going to dictate how much replacing the filters will cost.

Most under sink filtration systems will have filters that can easily be changed by the end-user (as opposed to needing to employ a plumber or specialist) but there may be a significant difference in cost between different manufacturers, even for the same type of filter.

For this reason it is always best to look up the cost of replacement filters before committing to buy an under sink water filtration system as a cheap unit which requires expensive filters may cost much more over its lifespan than a more expensive filter with cheaper filter cartridges.

The availability of replacement filters should also be considered when selecting a water filter – most manufacturers offer replacement cartridges on Amazon or your local hardware store but some can be harder to attain and this can lead to higher costs or longer lead times.  Remember, when the filter cartridges is at the end of its life it is no longer able to provide filtration to its usual standard and this is reflected in the quality of water coming from your tap.

Whilst most filters of the same type will be expected to last for roughly the same amount of use, some can last much longer and these are usually more expensive when the time comes to change them.

Most manufacturers claim that activated carbon filters should last between 3 and 12 months, with 6 months being a common projection while KDF filters are usually expected to last much longer.

Ease of Installation 

This is another often overlooked factor when it comes to buying an under sink water filter, and one which you won’t usually find reliably described on the box.

Amazon reviews are a great place to check out feedback from customers who have bought the product and lived with it for sometime… they’re especially helpful for insight into how the products fare over time and any problems which may arise later.

Ease of installation is one of these factors.

The cost of engaging a professional plumber to install an under sink filtration system is certainly going to outweigh any saving made by opting for a cheaper unit, and while most manufacturers will downplay the complexity of installation only first-hand user experience will give you a true picture of the ease with which a filter is installed.

Price and Durability 

The price of an under sink water filter can dictate not only its features but also the quality of the filters’ construction and its longevity.

We have seen many reports of budget filters which have worked well out of the box however after a couple of filter changes the seals begin to give way causing leaks and homeowner expense.

Durability is an indicator of how well the product will perform over time – as with all products involving water, seals and  o-rings are the most common failures and while the best under sink water filter manufacturers have after-sales departments who can provide spare parts it is always worth checking the availability of replacements before buying.

What is an Under Sink Water Filter?

As the name suggests, an under sink water filter is installed beneath a sink (usually in the kitchen) and connects to the incoming water supply.

Water passing through the filter is purified and delivered from the faucet of higher quality with fewer contaminants, tastes and odors.

How do Under Sink Water Filters Work?

Different types of under sink water filters

There are 3 defined types of under sink water filters – Conventional, Simple and Reverse Osmosis… we’ll describe the differences below.

Conventional

Conventional under sink water filters connect into the existing cold water service to the sink and feed a separate faucet (usually included with the filter kit). 

These systems can be more complicated to fit owing to the plumbing amendments required to accommodate the tee which feeds the new filter.

Filter life in a conventional system is usually improved, as the filtered water is drawn off separate from the mains cold feed from the existing faucet. 

Simple

Simple under sink water filters are fitted in line to the cold water supply to your existing faucet.  This minimises complications when installing as fewer plumbing changes are required, and it also removes the need to drill worktops and fit the additional filtered faucet.

Simple water filtration systems tend to require replacement filters more regularly because they are testing all water to the outlet, which can be a significant increase on filtered water required for drinking in a busy family home.

Reverse Osmosis

Reverse Osmosis (RO) filters work differently from other filtration systems.

Most other filters use the incoming water pressure (either pumped from a well/borehole or from a municipal supply) to push feed water through filtration devices designed to trap sediments, destroy organic particles such as bacteria and filter out contaminants like pesticides and heavy metals (depending on the model).

RO uses pressure across a semi-permeable membrane to force pure water to one side of the membrane while contaminants remain on the other.  This results in a volume of purified water which is stored in a tank for use at the faucet, and a concentrated brine mixture containing all of the contaminants, which is then flushed to drain.

The nature of the flushing process means that a significant volume of water is wasted with RO systems, and the need for pre filters and a storage tank results in more plant needing to be situated below the sink.

Under Sink vs Countertop Filters

Under Sink Filter Pros and Cons

Pros

  • Hidden within cupboard unit
  • Easily accessed for filter changing and maintenance 
  • Provide effective filtration to dedicated or existing faucet
  • Wide range of models available
  • Cheaper than whole house filtration systems 
  • Easy to fit

Cons

  • Only filters water to one outlet 
  • Can be awkward to install depending on cupboard size 
  • Can take up space in cupboard 
  • Leaks can go unnoticed

Countertop Filter Pros and Cons

Pros

  • Small 
  • Easy to access for maintenance and filter changes
  • Leaks are obvious as unit is in full view

Cons

  • Slower filtration rate
  • Take up space on kitchen worktop

Under Sink vs Whole House Water Filter

Which of these filter types best suits your requirements?

Cost

Whole house filtration systems are more expensive to purchase than undersink water filters and are usually installed by qualified professionals.  The installation cost alone of a whole house water filtration system will usually be more than the outright cost of an undersink filter.

 

Filtration

While whole house filters are usually installed within the basement and connected to the main incoming water supply, under sink water filters are installed directly below one outlet.

This means that when using a whole house filtration system, all water through all of the outlets in the property is filtered including dishwashers, washing machines and showers whereas an under sink filter system only filters water to one faucet.

Running Costs

As they usually treat more water, it is common for whole house filtration systems to require either more regular filters changes, or the filters are more expensive to buy outright when compared to under sink water filters.

Capacity

Whole house filtration systems are capable of filtering large volumes of water instantaneously while under sink filters can take time to fill just one glass.

Summary

If you can afford to install a whole house water filtration system, they are undoubtedly a superior option for providing clean, pure water to all areas within your home. 

Unless living in areas of particularly poor water quality, most people only require filtered water to improve the taste and so often the expense of a whole house filtration system is unjustified when an under sink water heater can provide the filtered water you need.

Why Use an Under Sink Water Filter?

There are many benefits to using an under sink water filter in your home:

  • Improves taste of drinking water
  • Removes contaminants which can cause short term and long term illnesses
  • Take up very little space
  • Very affordable way to improve water quality
  • Saves money on buying bottled water, as well as plastic waste
  • Easy to install without a plumber

 

The reality is that water quality is becoming more widely discussed in America, and catastrophes such as those seen in Flint, Michigan have made more and more people aware of potential contaminants within their water supply.

Many people take a “safety first” approach and install some form of water filtration to improve their tap water and reduce the risks posed by poor water quality and under sink water filters are a simple, cheap and reliable way to achieve this.

Installation and Maintenance Suggestions

How to Install an Under Sink Water Filter

The installation method will vary according to the model of under sink water filter that you purchase and you should always follow the manufacturer’s instructions however fitting the units will usually follow the same direction:

  1. Isolate your water supply and switch on the tap until any excess pressure and water has drained.
  2. If your filter has a dedicated faucet, fit this to the worktop by drilling a hole in the desired position and inserting the stem.  Secure using the fixing provided.
  3. Fix the filter body within the kitchen cupboard unit.
  4. Connect the existing cold water feed to the new filter.  If using a simple under sink filter, this will connect in line to your existing tap.  If using a conventional filter, you will need to cut a tee into the cold water feed and connect one side to the existing faucet pipework and the other side to the new filter.
  5. Connect and tubing and ensuring joints are tight.
  6. Close the taps and slowly switch the water back on. 
  7. Reopen the taps to vent any air from the cold water pipes – switch off again once water runs through normally.
  8. Check all joints for any sign of leaks.
  9. Flush the filter through as directed by the manufacturer, usually for 5-10 minutes
  10. Your under sink water filter is ready to use!

 

When Do You Need to Change the Filter Cartridge?

The manufacturer will always include guidelines for the expected cartridge filter life within the product literature however as you get used to using your under sink water filter you may notice some early warning signs that the filter is coming to the end of its life.

Flow rate is reduced 

This can be a sign that the tiny pores within carbon filters are becoming blocked as they reach capacity.  Check that all valves are properly open but if the flow rate to other outlets is unaffected, it is time to buy a new cartridge.

Changes to Taste 

As a filter becomes clogged with contaminants removed from the water supply it will begin to allow some particles through that would otherwise have been filtered – these ill affect the taste of the water at the faucet.

Manufacturer’s Recommendation

Manufacturers will always publish the recommended filter life, usually in the format of both gallons of water filtered and time installed.  You should always pay attention to these figures (even if you have to estimate the usage) – manufacturers spend thousands of dollars testing their products for quality and these limits are published according to the findings.

These values are usually the point when the quality of filtration begins to decline.

 

How to Clean and Replace Cartridges

Cartridge replacement will vary from model to model and will be detailed specifically by the manufacturer in the product manual.

  1. Switch off the water supply and open the faucet to relieve any pressure and drain water from the line.  If there are isolation valves on the pipework either side of the filter, close these too.
  2. Using a tool if required, open the filter housing – this will usually twist off using a wrench or special tool supplied with the filter.
  3. Remove the old filter cartridge.

TO CLEAN THE CARTRIDGE

  • Close up the filter housing without the cartridge.  Switch on the water supply and rinse the cartridge thoroughly under a tap. NEVER use detergents or any other cleaning agents.  Once flushed, switch off the water again and follow steps 1-2 to open the filter housing and reinstall the cartridge. Refit the top of the filter body and switch on the water supply, remembering to check for leaks.

TO REPLACE THE CARTRIDGE

  1. Insert the new filter block into the body. Refit the top of the filter body and switch on the water supply, remembering to check for leaks.
  2. Flush the new filter according to the manufacturer’s instructions, usually for 5-10 minutes.

Conclusion

Our comprehensive guide should have taken some of the confusion out of your decision as to whether an under sink water filter is right for you and given you some guidance on the best model for your needs and your budget.

For homes served by municipal water supplies, under sink water filtration systems are an effective, affordable and reliable way to improve the quality of water in your home, without having to make wholesale changes to the plumbing systems or laying out large sums of money for whole house filtration.

Latest posts by David Trinh

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