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. 

There are a few different types of models. Some contain reverse osmosis filtration and others do not. The models without RO tend to waste less water but the RO models are also very effective under the counter filters. In this review we will break down the top under counter filters on the market so that you can choose the right device for your home needs.

Top 10 Under Sink Water Filtration Systems

#1 Clearly Filtered 3-Stage
  • Filter Stages: 3
  • Dimensions: 13.75 x 3.5 x 16.75
  • Other: Quick DIY install & Lifetime Warranty
#2 Waterdrop G3
  • Filter Stages: 7
  • Dimensions: 18 x 5.7 x 17.8
  • Other: Most powerful filtration with RO
#3 Aquasana OPTIMH20
  • Filter Stages: 6
  • Dimensions: 12 x 4.5 x 12.5
  • Other: Great filter with RO
#4 Pelican 3-Stage
  • Filter Stages: 3
  • Dimensions: 15.5 x 5.25 x 14
  • Other: Quality affordable filter
#5 Aquasana 3-Stage Max Flow
  • Filter Stages: 3
  • Dimensions: 12 x 4.5 x 12.5
  • Other: Fast water flow & top brand
#6 Waterdrop 3-Stage Black
  • Filter Stages: 3
  • Dimensions: 15 x 5 x 14
  • Other: Zero waste & quality filtration
#7 ECO Soft 3-Stage
  • Filter Stages: 3
  • Dimensions: 15 x 5 x 14.5
  • Other: Affordable filtration
#8 iSpring RCC7AK
  • Filter Stages: 6
  • Dimensions: 15 x 8 x 18
  • Other: Reverse osmosis option
#9 CuZn UC 200
  • Filter Stages: 3
  • Dimensions: 5 x 5 x 15
  • Other: Compact option
#10 APEC WFS 1000
  • Filter Stages: 3
  • Dimensions: 6 x 15 x 12
  • Other: Middle of the line

Best Under Sink Water Filter Reviews 


1. Clearly Filtered 3 Stage


Our #1 recommendation for an under sink water filter is the Clearly Filtered 3-stage under sink filter system.

Clearly Filtered is one of the top brands in the water filtration market and for good reason. This filter removes 99% of 232+ contaminants and is one of the simplest under counter water filters you can purchase.

The 3 stages of water filtration consist of:

  1. Premium carbon priming filter (granulated coconut carbon removes chlorine, tastes, odors, cloudiness, and colors)
  2. Heavy metal and VOCs Filter (removes 99% heavy metals, pesticides, herbicides and more)
  3. Fluoride & arsenic filter (removes 99% of fluoride)

One of the biggest differentiators of this Clearly Filtered product is the ease of installation. Installation takes 15 minutes or less and doesn’t require a plumber! It is also a perfect installation for renters because it’s easy to remove and not permanent. 

Also, this filter has a 2,000-gallon filter life and stainless steel hoses. The design is sleek and it fits easily under your counter leaving you with plenty of space for other appliances.

Lastly, Clearly Filtered offers a lifetime warranty and this model is at a reasonable price point compared to other similar models on the market. 

If you’re looking for the best under the sink filter for your home then Clearly Filtered’s model you need to purchase. You won’t be disappointed.

Clearly Filtered


  • Lifetime warranty
  • Top of the line 3 stage filtration
  • Super easy to install and replace
  • Filter life 2,000 gallons
  • Filters out 99% of 232+ contaminants
  • Just as good or better as a system with RO


  • Not cheap but worth it for lifetime warranty and quality

2. Waterdrop G3


Coming in at #2 is the Waterdrop G3 reverse osmosis under counter system.

This is one of the most powerful under the counter filters with an impressive 400 gallons per day capacity which would suit even a large household.

This model also lacks a tank and is a true tankless reverse osmosis under sink option.

Not to mention Waterdrop has a sleek design that fits well under the sink.

The filtration quality of this system is top notch removing 99% of contaminants including fluoride. It has a 7 stage filtration system which is one of the most effective and thorough filtration systems on the market. 

If you’re looking for an under counter option that uses reverse osmosis filtration to get your water pure and clean then this system from Waterdrop is your ideal choice. 



  • Largest capacity & most powerful system
  • Uses reverse osmosis filtration
  • Sleek good looking design that fits well under sink
  • 400 gallons per day capacity
  • 7 stage filtration


  • One of the more expensive models but if you can afford it it’s worth investment

3. Aquasana OPTIMH20 RO+ Claryum


Our #3 pick is the Aquasana OPTIMH20 reverse osmisis and claryum.

Aquasana is one of the leading brands in the water filtration market and they product reliable top quality products that you can rely on to get your clean, pure, tasty water.

This model from Aquasana provides premium filtration technology with reverse osmosis. It’s tested and proven to remove fluoride and 87 additional contaminants. 

They conduct rigorous testing on their products and this model is certified to NSF/ANSI standards so you can be certain it is effective.

The filter is super easy to replace and you can get clean water fast with a 0.5 GPM flow rate.

Overall, if you’re looking for a top model with 6 stage filtration, reverse osmosis, and one of the leading brands that you can rely on then this OPTIMH20 model is a great choice. 

Aquasana RO


  • Rigorously tested and certified to NSF/ANSI standards to remove 87 contaminants and fluride
  • 6 stage filtration system with reverse osmosis
  • Reliable and trustworthy brand you can count on
  • Affordable price point


  • Not too many downsides of the product

4. Pelican 3 Stage

Our #4 choice is the under counter filtration purification system by Pelican Water.

The PDF-1000VF system is a 3 stage filtration system that is IAPMO certified to NSD/ANSI, has a 1,000 gallon capacity, doesn’t waste water or electricity, contains a metered flow control, and it’s simple to install.

Pelican is a trustworthy and reliable brand and you can count on them to deliver a system that provides clean tasty water.

This system removes 99% of bacteria, cysts, viruses, chlorine, lead, and particulates.

Overall, if you’re looking for another affordable quality system then this model from Pelican is one to consider.

pelican undersink


  • Removes 99% of contaminants
  • Rigorously tested and cerftified to standards
  • Trustworthy and reliable brand
  • Affordable price point


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

5. Aquasana AQ5300 3-Stage Max Flow

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.


  • Tool-free filter change
  • Good flow rate


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

6. Waterdrop 3 Stage Black

Our #6 pick is the Waterdrop 3 stage ultra filtration under sink system.

Waterdrop ultra filtration system does not require an undersink electricity supply and produces prime-quality purified water with zero waste water. The ultrafiltration membrane has a pore size of 0.01 micron, so it can filter out most of the contaminants in water.

It also has a cutting edge integrated waterway to prevent water leakage, which allows you to replace the filters without cutting off the water supply.

Overall, this system from Waterdrop is an innovative, all in one, intelligent purification system that is super cost effective and easy to install. It is recommend for anyone looking for one of the best under sink filters on a budget.



  • Low cost and high quality system
  • Innovative technology
  • 3 stage quality filtration
  • Sleek good looking design that fits nicely under sink
  • Easy to install and maintain


  • Not as powerful as their G3 model
  • Smaller capacity than the G3

7. Ecosoft 3-stage High Capacity

Ecosoft’s 3-stage tankless under counter water filter was a real surprise for us and snuck into the top 10.

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 around $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, this is another good budget option if you’re not willing to invest in one of the top picks.


  • Affordable setup kit and filters 
  • Faucet included
  • Easy installation
  • Very affordable budget option


  • Lower flow rate


8. iSpring RCC7AK

Coming in at #8 is the iSpring RCC7AK model.

This model has a 6 stage filtration with alkaline remineralization and it is a reverse osmosis system.

It removes 99% of harmful contaminants and has top of the line RO filtration technology.

Many users have reviewed this product and the overall consensus is that it is one of the top reverse osmosis under sink models at an affordable price.

The company also has excellent tech support and the machine can be installed with the help of a plumber pretty easily.

Overall, if you’re looking for a reverse osmosis under sink option this is another good product to consider. 



  • 6 stage filtration using reverse osmosis
  • Good customer service
  • Good overall customer feedback
  • Affordable


  • Wastes more water than a non-RO option
  • Bulkier and takes up more space under sink

9. 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 – that’s a pretty long time.

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.


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


  • Larger than other under sink filter units

10. APEC WFS 1000

Last on our list at #10 is the APEC WFS 1000 model.

This is another budget option that offers good filtration at an affordable price.

It’s guaranteed to remove chemicals, taste and odors and has a 3 stage filtration system with 2 super capacity carbon blocks and a super capacity sediment filter.

This product is also made in the USA, it’s earth friendly, and easy to install.

Overall, this model does not match our top picks for filtration or product quality but if you’re looking for an average budget option then it’s worth a look.

apec wfs


  • Affordable price
  • Effective filtration
  • Made in USA


  • Not as effective as our top picks
  • Brand is not as reputable
  • Just ok

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 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 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.

You can see our best whole house reverse osmosis systems here.

Under Sink vs Countertop Filters

Under Sink Filter Pros and Cons


  • 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


  • 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


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


  • 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?


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.



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.


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.


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.


  • 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.


  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.


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.

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