12 Best Under Sink Water Filters of 2021 Compared & Reviewed

Best Under Sink Water Filter
Photo: reverseosmosissystem.review

Clean, odor-free, great-tasting and safe water is one of the basic needs of any home. And one of the easiest ways to ensure that you have it is by investing in the best under sink water filter.

A good under sink water filter comes with many benefits with key among them being the fact that it does not eat up any counter space and will look neat under the sink.

Also, these water filters are low maintenance as they require less frequent filter change, are more efficient thanks to the multi-stage filtration and they allow a strong water flow rate.

But, if you want to get these and other benefits, you need to get a good under sink water filter. Our buying guide and reviews below will explain how to go about this.

What to Check Before Buying Best Under Sink Water Filters?

How to Buy the Best Under Sink Water Filter
Photo: aloneat.home.blog

There are various important things that you need to keep in mind when shopping for the best under counter water filter because all are not built the same. They include the following.

1. Compatibility

The first factor to look out for when shopping is whether the water filter is compatible with your current sink and plumbing setup or not as it will not work for you if it is not compatible.

Luckily many manufacturers will build their under sink water filter to work with most sinks. But, it is important to note that some might require a special adapter and other hardware to work with your setup.

Others will also need some plumbing modifications, and so it is important to pick what you find most convenient or will not require you to spend a lot of extra cash before you can use it.

2. Simple or Convectional Under Sink Water Filter

As you are picking an under sink water filter, you will also need to decide on the right type for you. Here you will often need to choose between the simple and conventional types as each has its pros and cons.

Simple Under Sink Water Filter: Despite being called simple, the working mechanism of these water filters is quite complex. Their name comes from the fact that it is simple to install and not from how it works.

With the simple under sink water filter like CuZn UC-200, all the cold water will run through the filter, and it delivers the water through the regular faucet and not a separate one. What this means is that it does not filter hot water since it is connected to the cold water system.

These are generally cheaper types of water filter and will not require any sink or countertop modifications as they are simple to install. However, they will filter more water which means more frequent filter change.

Conventional Under Sink Water Filter: The conventional under sink water filters get their name from the fact that they were the first under sink filtration systems.

When installing a conventional water filter like the iSpring RCC7AK, you need to use a connector (usually a plastic tube) to divert the water from the cold water pipe to the filter and a dedicated faucet. Once the water is filtered, it will then be sent to a separate faucet for dispensing.

Only the water that gets to the faucet that links with the filter will be filtered, and so the regular hot and cold water faucets will dispense unfiltered water.

With the conventional filtration systems, filters will last long as they do not have to filter a lot of water and you can install them in most plumbing systems. But, you will need to dig an extra faucet hole on the sink or buy one that comes with two and it reduces the flow rate significantly.

3. Water Pressure

Nothing is more annoying than having to wait for what seems like ages for a glass of water to fill up, and so water pressure is always an important factor to take into account when choosing a water filter.

An under sink water filter with good pressure is even more important if you have low water pressure to start with.

The simple water filter will offer more pressure than the conventional types. But, the downside to this is that with the simple model water spends less time in the filter, and so it is possible for some contaminants to pass through.

4. Filter System

The filtration system that the filter uses matters a lot. Besides from the obvious choice between simple and conventional filters, you will also need to consider other things like the filtration stages.

Most top-rated under sink water filters use a multi-stage filtration system to ensure that most of the contaminants are trapped for cleaner and safer water.

Three-stage filtration systems like what you get on the Aquasana AQ-5300.55 are the most common ones, and they are often good enough. But there are some more efficient under sink water filters that will have 4 stages or even more like the 9-stage Home Master TMHP.

5. Ease of Installation

Many manufacturers will make under sink water filters for DIY installation, and so most are straightforward to install on your own.

However, the ease of installation will vary from one model and brand to the other. Other things like the availability of the necessary hardware and installation instructions by the manufacturer also determine the ease of installation.

Also, some will use your current faucet and are installed directly in-line which makes the more straightforward to install. Others may require you to drill a new faucet hole and buy a new faucet which can make them a little more tedious to install.

12 Best Under Sink Water Filters ​of 2021 Reviewed




Filtrete 3US-PS01

1. Filtrete 3US-PS01 (Best Overall)

  • 2,000 gallons filtration capacity
  • Faster filtration rate
  • More budget friendly water filter
  • No dedicated faucet required
iSpring RCC7AK

2. iSpring RCC7AK (Best Reverse Osmosis System)

  • More effective 6-stage reverse osmosis system
  • Higher filtration capacity
  • Simple DIY installation
  • Clear 1st-stage housing for simple filter inspection
Home Master TMAFC-ERP

3. Home Master TMAFC-ERP (Inventively-Designed 7-stage System)

  • 2,000 gallons filtration capacity
  • Highly efficient 7-stage filtration
  • Up to 80% reduction in water wastage
  • Full contact technology for added minerals in water
  • Easy change and long-lasting filters
Culligan US-EZ-1

4. Culligan US-EZ-1 (Best Budget)

  • 3,000 gallons filtration capacity
  • More budget-friendly
  • Quick connect fittings for easy filter change
  • More effective in reducing bad odors and tastes

5. APEC ROES-PH75 (Noise-free)

  • Super quiet filtration
  • Improves water taste greatly
  • Quick and easy to mount
  • Free faucet included
CuZn UC-200

6. CuZn UC-200 (Incredibly High Filtration Capacity)

  • 50,000 gallons filtration capacity
  • Good enough flow rate
  • Efficient multi stage filtration
  • Bacteriostatic and resistant mold and bacteria growth
Woder WD-S-8K-DC

7. Woder WD-S-8K-DC (Long-Lasting Selective Filtration)

  • 10,000 gallons filtration capacity
  • Selective filtration preserves important water minerals
  • No plumbing needed for installation
  • Complete with all required parts and components
Home Master TMHP

8. Home Master TMHP (More Efficient & Effective 9-Stage Filtration)

  • 2,000 gallons filtration capacity
  • Highly effective 9-stage filtration
  • Filtration system adds essential minerals to water
  • UV light included to kill microorganisms

9. APEC WFS-1000 (Durable & Dependable)

  • 2,000 gallons filtration capacity
  • High-quality and reliable construction
  • Faster water flow with no tank required
  • Removes chemical but preserves essential water minerals
iSpring RCC1UP-AK

10. iSpring RCC1UP-AK (High Water Flow Rate Guaranteed)

  • Relatively higher water flow rate
  • Efficient 7-stage filtration
  • Remineralization for better water quality
  • UV sterilizer included to kill viruses/bacteria
Aquasana AQ-5300.55

11. Aquasana AQ-5300.55 (Economical & Long-Lasting)

  • 800 gallons filtration capacity
  • Relatively cheaper to buy and operate
  • Zero water waste during filtration
  • Smart filter change alert
Doulton W9330958

12. Doulton W9330958 (Compact, Space-Saving)

  • 600 gallons filtration capacity
  • Compact and space-saving
  • Complete in-line system with everything required
  • More efficient ceramic filter
  • Durable plastic housing

1. Filtrete 3US-PS01 – Best Overall

Filtrete Advanced Under Sink Water Filter
Photo: Filtrete

  • Filter Capacity: 2,000 gallons (6 months)
  • Filter Stage: 1-stage
  • Flow Rate: 2.25 gallons per minute

By maintaining a flow rate of up to 2.25 GPM, this under sink water filter will ensure that you always get a water flow that is as close to normal as possible so that you do not have to wait for ages just to fill a glass.

Also, it does not require a dedicated faucet which is quite convenient as you can use it with your regular kitchen or bathroom faucet. And this means you will not incur any extra cost to use it.

Besides the fact you will not need to buy another faucet, this is also a relatively affordable under sink water filter as it is the second cheapest item in our list, which is another key reason why it is our best overall product.

Installation is quick and easy as you can do it in less than 30 minutes and get filter service life of up to 6 months or 2,000 gallons.

However, the single stage filtration is not always the most efficient or effective, but for such an affordable water filter the water quality that you get is still good enough.


  • Maintains high water flow rate
  • Quick and easy installation
  • Does not require a dedicated faucet
  • Relatively affordable


  • Single-stage filtration, not the most effective

2. iSpring RCC7AK – Best Reverse Osmosis Water Filtration System

iSpring 6-Stage Superb Taste Under Sink Water Filter
Photo: iSpring

  • Filter Stage: 6-stage
  • Flow Rate: 75 gallons per day

Besides getting rid of more than 1,000 different types of contaminants, this 6-stage iSpring under sink water filter also helps to improve the water taste by restoring healthy minerals and alkalinity.

It uses the more efficient and high-capacity reverse osmosis filtration process to ensure that you always get safer and healthier water. And because it is a multi-stage system, almost no contaminant can pass through it.

There is also see-through 1st stage housing that makes filter monitoring easy to ensure you know when you need to replace it. With the larger RO membrane, you will get a water output of up to 75 gallons per day which should be enough for most families.

Installation is also quite easy as the manufacturer provides all the necessary parts, instructions, and a video to make things straightforward.

But despite the installation being quite easy, it can be quite lengthy as it will take most people at least a couple of hours to get the filter running. Its many stages of filtration means it takes up more room, but this is a small price to pay to get clean and refreshing water.

More Detailed: iSpring RCC7AK Review


  • More efficient and high capacity reverse osmosis filter
  • Restores healthy minerals
  • See-through housing for easy filter inspection
  • Comes with all parts and clear instructions
  • Fits under all standard kitchen sinks


  • Easy but lengthy installation
  • Takes up a lot of cabinet space

3. Home Master TMAFC-ERP – Inventively-Designed 7-stage

Home Master TMAFC Artesian Under Sink Water Filter
Photo: Home Master

  • Filter Capacity: 2,000 gallons (12 months)
  • Filter Stage: 7-stage
  • Flow Rate: 75 gallons per day

Home Master uses an innovative design on their TMAFC-ERP to solve common RO system problems. This design includes having full contact and a permeate pump. And so you will not only get clean water but also one with all the important minerals and a great taste.

This top-rated under sink water filter has a 7-stage water filtration system that will provide highly pure water by removing most of the contaminants and chemicals. Also, it will produce more than enough water for the family thanks to the 75 gallons per day capacity.

Water wastage is reduced by up to 80% thanks to the built-in and non-electric permeate pump. This under sink water filter is also quite convenient and economical to use as it comes with a durable 2,000 gallons capacity filter that is also quick and easy to change.

Although it is quite louder than what most people expect, you will hardly notice the noise once you get used to it. And as expected the 7-stage system takes up more room under the sink but its efficiency and high performance make up for this.

More Detailed: HomeMaster TMAFC-ERP Review


  • Efficient 7-stage system for highly pure water
  • Durable and easy-to-change filter
  • Adds important minerals to water
  • Reduces water wastage


  • Will take up a lot of space under the sink
  • Quite loud when the tank is refilling

4. Culligan US-EZ-1 – Best Budget

Culligan EZ-Change Under Sink Water Filter
Photo: Culligan

  • Filter Capacity: 3,000 gallons (12 months)
  • Filter Stage: 1-stage
  • Flow Rate: 0.5 gallon per minute

While it will be up to one year before you need to replace the filters on this Culligan under sink water filter, it is still a super easy process thanks to the quick connect fittings on the filter cartridge.

You will not need to spend a lot of cash to get this water filter as it is the cheapest model on our under sink water filter review. Despite the highly affordable price tag, it still comes with a dedicated faucet.

The included filter cartridge is designed to not only get rid of most contaminants but also to get rid of bad odors and tastes. And it can filter up to 3,000 gallons of water.

This under sink water filter comes with all the necessary parts and hardware for installation, and it will work for most standard sink types.

However, the size of the filter and 0.5 GPM flow rate means that it will not be ideal for high volume filtration, but it should still be good enough for the average family sizes.


  • Highly affordable
  • Quick connect fittings
  • Removes bad taste and odor
  • Dedicated faucet included


  • Not for high volume filtration
  • Faucet handle can be annoying

5. APEC ROES-PH75 – Best-Noise-Free

APEC ROES-PH75 6-Stage Under Sink Water Filter
Photo: APEC Water Systems

  • Filter Stage: 6-stage
  • Flow Rate: 76 gallons per day

The 6-stage filtration system on this APEC under sink water filtration removes 99% of bacteria, cysts, chemicals, and other contaminants to make your water safe and healthy.

The noise-free filtration makes it hard to notice it when it in operation, and it also uses some durable and safe filter cartridges to provide up to 76 gallons of filtered water every day.

Besides helping clean the water, this filtration system helps to improve its tastes by enhancing its pH level and adding important minerals to make it even healthier.

Installation is relatively easy as the water filter comes with all the necessary parts including quick connect fittings and a dedicated lead-free faucet to make it ready for immediate use.

While the faucet quality is not the best and the water filter will produce a lot of waste, the water quality and taste makes these minor shortcomings that you can live with.


  • Noise-free filtration
  • Improves water alkalinity and taste
  • Relatively easy DIY installation
  • Quick Connect fittings
  • Lead-free faucet included


  • Produces a lot of waste
  • Faucet quality is still a little wanting

6. CuZn UC-200 – Incredibly High Filtration Capacity

CuZn UC-200 Under Sink Water Filter
Photo: CuZn

  • Filter Capacity: 50,000 gallons (5 years)
  • Filter Stage: 3-stage
  • Flow Rate: 2 gallons per minutes

Given the incredibly large filter capacity of up to 50,000 gallons or up to 5 years, it is safe to say that this is the best under sink water filter for the money in our list as it is also relatively affordable.

The 3-stage water filter delivers a relatively high flow rate of 2 GPM which is quite good when compared to others in our list and also out there.

Besides the long-lasting filters and high flow rate, this under sink water filter only takes a few minutes to install and all you will need is an adjustable wrench.

This water filter is bacteriostatic and will not be susceptible to the growth of mold or bacteria like the carbon only filters.

Although the installation instructions are a little minimal, this should not be a problem as this is an easy-to-install water filter.


  • Incredibly high filter capacity
  • Relatively high flow rate
  • Compact space-saving design
  • Not susceptible to mold/bacteria
  • Simple hassle-free installation


  • Instructions are a little too minimal
  • Does not seem to improve water taste significantly

7. Woder WD-S-8K-DC – Long-Lasting Selective Filtration

Woder 10K-Gen3 Under Sink Water Filter
Photo: Woder

  • Filter Capacity: 10,000 gallons (3 years)
  • Flow Rate: 2 gallons per minute

If you use municipality water this is the best under sink water filter for kitchen for you as it is designed to specifically for use with this regular tap water.

Its 10,000 gallons or 3-year filter capacity is the second highest on our list, and so if you hate changing filters frequently, this will be a good choice for you.

When it comes to the actual filtration, this water filter uses selective filtration to ensure that it only gets rid of contaminants and leaves the important minerals in your water.

Installation is quite straightforward as it comes with all the parts that you will need including direct connect hoses for use with standard water valves.

This under sink water filter also eliminates bad taste and odor so that you always get refreshing water.

Although it will reduce water pressure significantly, the 2 GPM flow rate is still adequate for most users. And despite replacement filters being a little hard to come by you should still find them online fairly easily.


  • Effective selective filtration
  • Relatively high filter capacity
  • Direct connect hoses for easy installation
  • Eliminates bad taste and odor
  • Comes with everything needed


  • Reduces water pressure significantly
  • Replacement filters not always available

8. Home Master TMHP – More Efficient and Effective 9-Stage Filtration

Home Master TMHP HydroPerfection Under Sink Water Filter
Photo: Home Master

  • Filter Capacity: 2,000 gallons (1 year)
  • Filter Stage: 9-stage
  • Flow Rate: 75 gallons per day

The 9-stage filtration system on Home Master’s HydroPerfection is the most efficient and effective in our under sink water filter review. And so with this filter, you will always get highly pure water that is free of chemicals, heavy metal, and other contaminants.

On top of cleaning the water and making it safer, this under sink water filter will add minerals to make it great tasting and healthier.

Also, it features a UV light that will destroy bacteria and microorganisms to make the water even safer. And the permeate pump will maximize water pressure while also reducing wastage.

The filters have a capacity of 2,000 gallons or 1 year depending on which comes first and are also simple and quick to replace.

But, this is the priciest item in our review. However, given the water quality and overall constructions, it is worth every coin.


  • Efficient and effective 9-stage filtration
  • Adds minerals for great tasting water
  • UV light destroys microorganisms
  • Permeate pump reduces wastage
  • Easy-to-replace filters


  • Relatively pricier

9. APEC WFS-1000 – Durable and Dependable Filtration System

APEC WFS-1000 Super Capacity Under Sink Water Filter
Photo: APEC Water Systems

  • Filter Capacity: 2,000 gallons (12 months)
  • Filter Stage: 3-stage

A highly durable and dependable filtration system is one of the key features that make the APEC WFS-1000 one of the best under sink water filters for kitchens out there.

Also, it is designed to eliminate the need for a tank as it has a good enough flow rate, and it does not require any flushing which means no water wastage.

The 3-stage water filter will also come with a sturdy lead-free chrome faucet and a 5-foot food grade tubing to ensure you always get safer water.

Besides getting rid of most contaminants and chemicals, this under sink water filter keeps important minerals to make the water taste better and ensure it is healthier.

While the instructions are a little confusing, installation should not be an issue as it is quite straightforward. For some users, the fact that this water filer is not for TDS removal might be a drawback but at its price range this is not a significant drawback.


  • Durable and dependable filtration
  • Does not need a tank
  • No water wastage and does not require a rinse
  • Keeps important minerals
  • Sturdy lead-free faucet


  • Instructions are a little confusing
  • Not for TDS removal

10. iSpring RCC1UP-AK – High Water Flow Rate Guaranteed

iSpring RCC1UP-AK 7-Stage Under Sink Water Filter
Photo: iSpring

  • Filter Stage: 7-stage
  • Flow Rate: 100 gallons per day

With an output or flow rate of an impressive 100 gallons per day, the iSpring RCC1UP-AK is your ideal choice if you are on the hunt for the best high flow rate under sink water filter.

Besides having the highest flow rate on our list, you can also be confident that the water you are getting is clean and safe. And this is mostly thanks to the thin-film semipermeable membrane filter.

The filter is handy for remineralization of the water to balance the pH and introduce important minerals to make it healthier.

There is an ultraviolet sterilizer that will kill the viruses and bacteria, and a pre-equipped booster pump that operates super silently. Installation is quite simple as the water filter will fit under most standard sink cabinets.

Some users will find this water filter quite bulky and large and relatively pricier as it is the second most expensive item in our list.

However, the bulkier design is because it is an efficient 7-stage system that delivers up to 100 gallons every day which explains the relatively higher price tag. And you can also be confident it will be worth every coin.


  • High flow rate
  • Silent booster pump included
  • Streamlined DIY installation
  • More efficient semi-permeable membrane
  • Ultraviolet sterilizer included for killing viruses/bacteria


  • Quite large and bulky
  • A little pricier

11. Aquasana AQ-5300.55 – Economical and Long-Lasting

Aquasana 3-Stage Under Sink Water Filter
Photo: Aquasana

  • Filter Capacity: 800 gallons (6 months)
  • Filter Stage: 3-stage
  • Flow Rate: 0.5 gallon per minute

This 3-stage Aquasana under sink water filter is designed to ensure instant access to clean and healthy water and with zero water wastage. It is not only a more affordable unit to buy but also does not cost much to use.

It does not add any harmful contaminants to your water when filtering and instead removes up to 99% of 77 common contaminants like lead, pharmaceuticals, and mercury.

The water filter is relatively easy to install in just a few minutes and changing the filter is equally easy. You do not need to guess when you get to the 800-gallon or 6-month filter change mark as it has a smart indicator to alert you.

Also, you will get all the necessary parts that you need for DIY installation in the package and there is a stylish faucet.

Although you cannot buy the replacement O-rings separately, this is not a problem if you sign up for the manufacturer’s filter supply program as you will never need to.


  • Economical to buy and use
  • Zero water wastage
  • Smart filter change alert
  • Comes with all required parts for DIY installation
  • Stylish faucet included


  • Replacement O-rings cannot be purchased separately

12. Doulton W9330958 – Best Compact, Space-Saving

Doulton W9330958 SuperCarb Under Sink Water Filter
Photo: Doulton

  • Filter Capacity: 600 gallons (6 months)
  • Filter Stage: 4-stage
  • Flow Rate: 0.9 gallon per minute

The compact design of the Doulton W9330858 makes it a great pick for users that are looking for something that takes up little cabinet space.

It is also a well-built water filter with a highly durable plastic housing, and it comes with a highly efficient ceramic filter that will provide cleaner and safer water.

This under sink water filter is a complete in-line system that will come with most of the things you need for installation including push-fit connectors.

While the 600-gallon filter capacity is by far not the highest on our list, it is still quite good and the 0.9 gallon per minute flow rate should be enough for many users.

The installation instructions are not very detailed, but this is not important because almost anyone can easily figure out how to set up this under sink water filter.


  • Durable plastic housing
  • Comes with the complete installation kit
  • Greatly improves water smell and taste
  • Top notch quality ceramic filter
  • Compact design takes little space


  • Instructions not very detailed

Under Sink vs. Countertop Water Filter

1. Under Sink Water Filters

When you do not want to clutter your countertop as you would with the countertop water filters, the under sink water filters are often the best alternative.

They are designed to filter huge amounts of water just like the countertops, but they generally have a longer filter life than the latter as some models can go up to 5 years without requiring a filter change.

These water filters are out of sight which creates a neat look and will not weigh down your faucets. And to make things even better, they also maintain a great water filtration rate.

However, these are quite large filters that will take up a lot of cabinet space, and they are harder to install than the countertop types as sometimes you might need some professional plumbing modifications.


  • Good water flow rate
  • They are out of sight
  • Will not take up precious counter space


  • Larger and will take up more cabinet space
  • May require professional installation

2.  Countertop Water Filters

Countertop water filters are easier and quicker to install than the under sink types, and so they are a better choice for those that prefer DIY installation.

Like the under sink water filters, they are also designed to filter a lot of water. Although they take up significant counter space, they are still smaller and more compact.

These water filters are less likely to clog like the carafe types. However, they offer a relatively slower filtration rate and they can clutter the countertop and ruin the design or decor.


  • Small and compact
  • Relatively easier to install
  • Less likely to clog


  • Slower flow rate
  • Can clutter countertop

Buying Advice: If you prefer something easy to install and do not mind a slower filtration rate and having to change filters more often, the countertop water filters are your best pick. But, if you are looking for something that will be out of sight and will provide a good water flow rate, go for the under sink models.


An under sink water filter provides one of the easiest and most cost-effective ways of making your tap water cleaner and safer. 

Finding the best under sink water filter should now be easy as you only need to keep the points in our buyer’s guide above in mind and use our top 12 under sink water filter reviews for recommendations.

And from these review, the Filtrete 3US-PS01 as besides having an efficient filtration system it is also budget-friendly and straightforward to install.