10 Best Under Sink Water Filters – [Reviews and Guide]

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by Lisa Ward

Updated on: 02/17/2021

Tap water can contain contaminants which are bad for your health or make the water taste bad. Plastic water bottles are bad for the environment and the costs add up, which is why the most efficient way to always have clean, delicious water is by using a water filter.

Under Sink Water Filter Reviews

We wanted to know which model was the best under sink water filter and we set out to find out. In this under sink water filter guide we are going to give you a list of the best under sink water filtration systems that we could find online. These products are all from reputable manufacturers with a reputation for producing great water filtration products.

In our list of the top ten under sink water filters we have included our picks for the winner and runner up as well as our picks for different product categories like tankless or high chlorine reduction. There are many features to consider when shopping for an under sink water filter. Keep reading past the reviews for a detailed buying guide that lays out what important features you should consider when shopping for a water filter.

#1 The Winner

iSpring RCC7AK Under Sink RO Water Filter System

iSpring RCC7AK

  • NSF Certified
  • 6-stage Filtration
  • High-capacity
  • Reverse Osmosis
  • Alkaline Remineralization

Our pick for the number one under water sink filter currently on the market is the iSpring RCC7AK. It uses the latest filtration technologies to return a healthy alkalinity and balance of minerals to the tap water. It effectively removes 99% of chlorine, lead, fluoride, asbestos, and other contaminants from the water.

Using this filter will make your tap water both more healthy and better tasting. Unlike most filtration systems which only use one or two types of filter, this system has six stages of filtration including alkaline remineralization. This step is important for having great tasting water since regular water filters remove some healthy minerals which makes for acidic water with a less natural taste.

Each component of the system is meticulously designed and manufactured for maximum quality and performance. The purchase comes with a European style kitchen faucet as well as all of the parts you need to connect the filter. Also included in the box are the six filters: three pre-filters to remove sediments, an ultra-fine filter to remove contaminant particles as small as 0.0001 microns, a GAC filter for further purification, and then the alkaline remineralization filter.

The filter is backed by a manufacturer's warranty on the parts. It can be easily installed yourself using the easy to follow instruction manual included in the box and the visual learning resources they have online. The size of the filtration system is small enough to easily fit under most standard sized kitchen sinks. Once it is installed you can enjoy on-demand filtered water for years to come.


#2 Runner Up

CuZn UC-200 Under Counter Water Filter

CuZn UC-200

  • Eco-friendly
  • 5-years Per Filter
  • 5-year System Warranty
  • 3-stage Filtration
  • Bacteriostatic

For our pick for the runner up best under sink water filter we have selected the CuZn UC-200. The UC-200 is a great under sink water filter for homes with municipal water, but it is not yet approved for use with private well water. It is a super compact and lightweight system which weighs only 8 lbs. It will hardly take up any room at all under the sink and it is very easy to install. It is an effective water purifier, but keep in mind that this filter is not a water softener. It allows healthy minerals to remain in the water which means it will not solve issues caused by hard water such as mineral deposits.

It has a 3-stage filtration process which purifies the water. It uses a KDF-55 filter and a coconut shell carbon filter to efficiently remove sediments, particles, and contaminants from the water. It is designed to remove the harmful contaminants while allowing healthy natural minerals to remain in the water. Some carbon filters can get moldy over time, but not the CuZn UC-200 filter. They are bacteriostatic which means they are highly resistant to the growth of bacteria.

You are guaranteed to get up to 5-years of high-quality performance when you use this filtration system. After 5-years you should use a chlorine test strip to determine whether you need to replace the system. If the filter stops working before 5-years this is covered by the free warranty from the manufacturer. The manufacturer also has a “comprehensive install support policy”. This means that if any additional parts are needed for installation they will send them to you free of cost.


#3 5-stage RO-system

APEC Water System ROES-50 RO Water Filter System

APEC Water Systems ROES-50

  • Reverse Osmosis
  • Made in USA
  • Removes 99% of Contaminants
  • WQA Certified
  • 2-year Warranty

This 5-stage water filtration system uses high-quality RO filters to remove 99% of harmful continents from the water including lead, fluoride, and chlorine. It makes the water healthier to drink and better tasting too. The system has been heavily tested and certified by third party organizations such as the WQA (Water Quality Association). Having been awarded the gold seal from the WQA, this product complies with the highest quality of standards in the water filter industry. The manufacturer has been making water filters for the last 20-years and they are exceptionally good at creating these products.

Each of the parts of the filtration system are designed and manufactured with quality and performance in mind. The parts are covered by a 2-year limited warranty from the manufacturer so you have peace of mind when you buy that your investment is covered. You can use this water filter system to have clean, filtered water on-demand for years. The filters use carbon filtration to remove harmful contaminants. Carbon filters are eco-friendly and highly efficient at safely filtering water.

It is super easy to install this filtration system. The size of the system is small enough to fit under most standard sinks and it comes with a faucet included. The system is streamlined for maximum efficiency in installation and maintenance. There is an easy to follow instruction manual included in the box with purchase and the company has installation videos online if you need extra help. This filter makes water taste better and it is more healthy for you.


#4 Best Direct Connect Water Filter

Waterdrop 15UA Under Sink Water Filter

Waterdrop 15UA Under Sink Water Filter System

  • Stainless Steel
  • 3-stage Filtration
  • 2-years/16,000 Gallons Per Filter
  • NSF Certified
  • 97% Chlorine Reduction

This Waterdrop filter system uses three-stages of filtration to remove harmful contaminants from the tap water. It is highly effective for reducing the amount of chlorine in the water, which is the source of the bitter taste that a lot of people dislike about tap water. Using this under sink water filter system is an easy way to have affordable filtered water whenever you need it so you can stop buying water bottles. It is made with top of the line components and high-quality materials which are lead and BPA free. 

The Waterdrop under sink water filter system is compatible with kitchen faucets with a ½” or ⅜” female NPT thread. If you are unsure whether or not it is the correct type of connection for your sink you should give the company a call to ask. They have a friendly customer support line which is available for questions about installation or warranties.

NSF (National Science Foundation) has tested this water filtration system and it met their standards of quality for 42 different tests. It effectively reduces sediments, contaminants, and bad tastes from tap water. The best thing about direct connect filters like this is how easy they are to install. It can be hooked up with a cold water connection only. The parts are made to easily connect using “push-to-connect” and “twist-and-lock” techniques. It comes with everything you need to quickly connect the system with your water faucet.


#5 Runner up - Best Direct Connect

Frizzlife under sink water filter system

Frizzlife Under Sink Water Filter System

  • NSF Certified
  • High Precision
  • 5-minute Installation
  • 2-stage Filtration
  • 2.0 Gallons Per Minute

Our runner up selection for the best direct connect under sink water filter is the Frizzlife system. It is a 2-stage filtration system which produces a heavy flow of water up to 2.0 gallons per minute. This means that it produces water faster than many of the other top-rated water filters on this list. That is one of its many benefits. Its other benefits include improving the taste of the water and removing harmful chemicals like fluoride and chlorine. It has a high precision filtration process which removes 99.99% of contaminants.

Although it effectively removes particles as small as 0.5 microns, it allows healthy minerals to remain which gives the water a more natural taste. Everything about the filtration system is designed to be as eco-friendly as possible. They have used a minimal amount of plastic in the construction of the system and you can recycle the parts when you are done with it.

One of the most impressive features of this system is how high capacity the water flow is. A lot of water filters produce filtered water at a much slower rate, but with the heavy flow of this system you can do tasks like wash dishes and rinse vegetables. This allows you to use filtered water for more than just drinking with no time wasted. Each of the filters lasts for 2-years or 1,600 gallons before it needs to be replaced, but you can replace it every six-eight months instead if you want the cleanest possible water.


#6 Best Tankless RO system

Waterdrop RO Water Filtration System

Waterdrop RO Reverse Osmosis Drinking Water Filtration System

  • 400 Gallons Per Day
  • Reverse Osmosis
  • BPA-free
  • 7-stage Filtration
  • Lead-free

The best tankless RO system on our list is the tankless RO system from Waterdrop. One of the issues with regular water filters is that the flow of water is too slow. This Waterdrop tankless system has a high flow of water for doing various tasks including producing great tasting drinking water. The purchase comes with three of the replaceable filters as well as a brushed nickel faucet for a seamless connection.

This under the sink filter is top of the line. It takes about thirty minutes to install the system and then you can enjoy clean water on demand for many years. It takes only three seconds to replace the filter which keeps maintenance super low. The NSF has tested and certified this filtration system for multiple standards of performance. It removes 90% of the total dissolved solids (TDS) from the water and passes 400+ laboratory tests to see how it performs.

All of the components of the filtration system are made with top of the line materials which are both BPA-free and lead-free. The filtration system works in layers. There is an activated carbon filter which is sandwiched between two PP cotton layers. After that there is a 7-layer RO membrane which filters out contaminants as small as 0.0001 microns. Next comes the reverse osmosis membrane layer and lastly there is another carbon layer to polish the taste.


#7 Best For Well Water

Home Master TMAFC-ERP Artesian undersink water filter

Home Master TMAFC-ERP

  • Reverse Osmosis
  • 7-stage Filtration
  • NSF Certified
  • 5-year Limited Warranty
  • One Filter Lasts One Year or 2,000 Gallons

Not all water filters are approved for use with a private well, but this one is made for it. Well water can be more challenging to filter than regular municipal water and it requires a more effective system. The Home Master TMAFC-ERP filters out harmful chemicals like chlorine and lead, but adds in healthy minerals like calcium and magnesium. Having minerals in the water makes it taste better and adds nutritional value to the water.

The Home Master system is made out of high-quality parts which are completely BPA and lead-free. Other reasons to invest in this well water filtration system include that it is registered and certified with the NSF. The NSF is an organization which tests water filters to see how their performance measures up against industry standards. This filter is certified to remove 99% of chlorine, lead, fluoride, plastic, and dissolved solids. All of the parts are manufactured in the United States as well.

Within the system is a high-quality 7-stage carbon filter. The water must pass through over eight inches of carbon and is purified the entire way. A benefit of this model of water filter is that there is a Fast Flo RO! kit which is included that has larger tubing for an increased flow of water. It is designed to be easy to install and maintain, with no wrenches required. You only have to change the filter once a year.


#8 High Chlorine Reduction

Waterdrop 10UB under sink water filter system

Waterdrop 10UB Under Sink Water Filter System

  • Stainless Steel
  • One Filter Lasts For One Year
  • NSF Certified
  • Easy Installation
  • 0.75 Gallons Per Minute

Our pick for the under sink water filter with the best high chlorine reduction is the Waterdrop 10UB under sink water filter system. Waterdrop is one of the best brands for finding great water filters and this system is no exception to the high standard of quality you can expect to find from all of their products.

The NSF has rigorously tested the design and performance of the system to ensure that it meets their standards. It has passed 42 total NSF tests and they found that the system effectively improves the clarity and taste of tap water. It is very good at filtering out the high level of chlorine which is found in most tap water.

Each filter lasts for about one year, or up to 8,000 gallons. The filter removes particles and contaminants from the water which can be harmful to the health or cause an unpleasant taste to the water. All of the materials used in the system are of the highest quality and contain no lead or BPA. This water filter system is a great choice if you want a sink faucet to go with it. It comes with a stainless steel faucet which seamlessly connects with the water filter.

Installing the filter is super easy with this system. It can take as little as three minutes to have the filter completely set up under the sink. The installation process uses “twist to lock” and “push to connect” techniques which allows the installation to be mostly tool free. The average homeowner can install this water filter easily without having any sort of experience.


#9 11-Stage UV Water Filter

Express Water UV RO water filtration system

Express Water UV Reverse Osmosis Water Filtration System

  • 11-stage Filtration
  • Faucet and Tank Included
  • BPA-free
  • 99% Removal Rate
  • Leak Protection 

Most filters use somewhere between one and five filters, which is why this 11-stage filtration system is much more powerful. It uses UV technology to sterilize the water from viruses and bacteria. This filter is a top of the line model. It removes more contaminants than most filters while also adding back in essential minerals to improve the taste. Harmful chemicals like fluoride, chloride, lead, arsenic, and more are filtered out by at least 99%.

This water filter system is an alkaline filtration system. Most regular filtration systems strip everything from the water including healthy minerals which leaves the water more acidic. This filter adds in magnesium, potassium, and calcium for healthier and better tasting water straight from the tap. The system comes with both a water tank and a faucet for a streamlined installation where all the parts work seamlessly together.

You can rest assured that your investment is protected because the filtration system is covered by a one year warranty from the manufacturer. Installation can be done even by the most inexperienced DIYers by following the instructions in the easy to read user manual (included in the box). The water tank on the filtration system automatically refills itself so that you can always have clean water when you need it. To prevent leaks, the water filter has a safety feature which detects moisture and shuts off automatically in the case of a leak.


#10 Ideal for RV

Waterdrop TSU water filter system

Waterdrop TSU 0.01μm Ultra-Filtration Under Sink Water Filter System

  • 3-stage Filtration
  • 2-years Per Filter 
  • “Smart” User Panel
  • Replace Filter in 3 Seconds
  • Water Quality Indicators

If you want an under sink water filter for your RV then we recommend that you check out the Waterdrop TSU under sink water filter system. It is a small, compact size which can easily fit under a small RV sink. It has a smart panel which is one of its most innovative features. The smart panel has water quality indicators so that you can check the water quality. When the filter is dirty and needs to be changed the panel will indicate this with a light. The indicator lights help to remind you to change the filter (which only needs to be changed every two years).

Installing the system is super easy even in an RV. It takes as little as five minutes to install the water filtration system and then you can enjoy clean, great tasting water for years before you have to change the filter again. It takes only three seconds to change the filter which is super fast. It has a longer-lasting and more effective filter than most regular water filters.

The system removes chlorine, fluoride, and harmful chemicals from the water. This improves the taste, clarity, and odor of the drinking water. In order to allow healthy minerals to remain in the water, the system does not filter out calcium, potassium, or magnesium. Having a healthy balance of minerals in the water gives it a more natural and less acidic taste.


Buying Guide

Now that we have told you about our top picks for the different product categories we are going to go into more detail about the features and benefits of under sink water filters that you should consider when shopping. Reading this buying guide will help you make the best well informed decision when it comes to which water filtration system is right for you.

Mother and daughter in kitchen

The Benefits of Under Sink Water Filters

Why do people use under sink water filters? There are many benefits to using these systems including water taste, water quality, and protecting the environment.


Water Taste Improvements

Girl drinking water from a water tap

One of the things that causes tap water to have a bad taste is high levels of chlorine. Water filters remove somewhere between 90% and 99% of chlorine from the water which makes it taste a lot better. Filtration also removes dissolved particles and other contaminants which could give the water a funny taste. Some of the top of the line filtration system included a remineralizer which adds in healthy minerals like calcium and potassium to make the water taste better.

Water Quality Improvements

Tap water can contain contaminants which are harmful to the health. Regulations allow for a certain percentage of these contaminants to remain in our water which is why having a water filter is important. Filtering out harmful chemicals in the water can protect your health and reduce symptoms of contaminated water like headaches, fatigue, and hard water mineral deposits.

Environment Friendly

Water bottles make up a huge percentage of trash in the ocean. Eliminating the need for water bottles by using a water filter instead will make your home much more eco-friendly. Under sink water filters use minimal amounts of plastic and the plastic they do use can be recycled. The filters are generally very long-lasting which makes waste minimal as well.

Maintenance

Most under sink water filters require very little maintenance. Installation can vary in complexity, but the maintenance itself usually involves no more than changing the filter every once in a while. With most filters reaching expiration between 1-5 years, there is very little maintenance to do to keep an under sink water filter working effectively.

How Under Sink Water Filters Work

An under sink water filter is a system installed below the sink which filters the water directly from the source. This allows you to have clean, filtered water directly from your tap whenever you need it. There are different kinds of water filters that are used to clean the water.

Different Types of Under Sink Water Filters

These are three main types of under sink water filters. Many of the top-rated models of water filters which are currently on the market are made with a combination of different types of filters to maximize the performance with the benefits of various kinds of filtration.

Carbon Filter

The most popular type of water filter is a carbon filter. Activated carbon is a powerful purifying agent which cleans the water naturally. As the water is pushed through the carbon filter it removes many of the contaminants and neutralizes the water. The carbon filter uses absorption to separate particles and chemicals from the water. Carbon filters are very effective for removing high chlorine levels.

Reverse Osmosis

With a reverse osmosis filtration system the water is pushed through a very thin mesh membrane which captures particles as the water goes through. Reverse osmosis removes everything from the water including the minerals that you do want, so RO filters work best when paired with a remineralizing alkaline filter.

Alkaline

Alkaline water filters use the process of electrolysis to raise the pH level of the water to make it less acidic. Alkaline filters strip less of the natural minerals from water that other filters do. Having essential minerals in your water is important which is why alkaline filters are a popular choice for water filters.

Features You Should Look For

When you are shopping for an under sink water filter keep each of the following features in mind.

Water Pressure

One of the main problems with an under sink water filter is that some systems have a very low flow, low water pressure stream of filtered water. This can be fine for producing a single glass of drinking water, but if you need filtered water for cleaning and other activities then you will want to pay more attention to what the water pressure is. This is often expressed as “gallons per minute” in the product descriptions.

Filtering Capacity

The filtering capacity refers to how much water can be filtered with each filter. This number can range from anywhere from 1,000 to 10,000 gallons per filter change. High capacity filtration systems are better because you can go longer in between filter changes. It can also refer to how many gallons of water per day the system can produce. Average under sink water filters can produce about 75 gallons of filtered water every day.

Ease of Installation

A lot of under sink water filter systems can be installed at-home easily. They use methods like “push to connect” and “twist to lock” for installation to make it a tool-free process that anyone can do. You want to make sure that the filtration system will integrate with your sink by checking the dimensions and the connection requirements.

Filter Change

One thing to consider about the pricing of the filtration system is how often the filter needs to be replaced and how much replacement filters cost. Some filters need to be changed every 3-6 months, but we have featured water filters in our review that can last for up to five years in between filter changes.

Cartridge Longevity

The filter cartridge longevity varies greatly in between different models. BRITA pitchers require you to change the cartridge every 4-weeks, but most under sink water filters have far more long lasting cartridges that last up to multiple years.

Micron Ratings

You will find that many water filtration systems list what their micron rating is. Microns are the measurement used to describe the size of particles in the water which are too small to see with the naked eye such as dissolved solids and minerals. The micron rating for filters usually ranges in between 0.5 to 0.0001 microns. The smaller the number, the more effective the filter is since it can filter out smaller particles.

Warranty

When you are shopping for a water filter do not forget to check out what warranty options are offered from the manufacturer. Most water filters will include a warranty between 1-3 years. The warranty will protect your investment by promising to replace any broken or defective parts before the warranty runs out.

FAQ

How often should you change an under sink water filter?

The amount of time between filter changes varies depending on the filtration system. Most average under sink water filters require that you change the water filter about every six months, but some systems only need a filter change once a year or less.

What happens if a water filter is not changed?

When the water filter is not changed the water quality can be bad. All of the contaminants which have been absorbed into the dirty filter can begin to leak into the water, making it worse than it was naturally. It is important to keep up with water filter changes. You may notice that the filter needs to be changed because the taste of the water changes/worsens. Some filtration systems have an indicator which tells you when it needs to be changed.

How do you install an under sink water filter?

Installing an under sink water filter includes making a connection between the water source and the filter system. The filter system is then connected with a faucet. Many of the latest filter systems on the market use tool-free installation methods which are incredibly simple. The installation time varies from 3-30 minutes. Some under sink water filter systems include a faucet with it so that the connection can be made seamlessly. Water filtration systems almost always connect only with the cold water source and never the hot water.

Conclusion

Using an under sink water filter is one of the best ways to improve your water quality. It is super convenient because it filters the water directly from the source so that you can get clean running water from your faucet. Water filters make water taste better, smell better, and improves the clarity. Health concerns from too much chloride or fluoride in the water can be remedied by switching to a high quality filtration system.

It is cheaper than water bottles, more eco-friendly, and under sink filters are hidden out of sight so they do not take up counter space in your kitchen/fridge like a filter pitcher does. We hope that after reading our dedicated best under sink water filter guide that you have a better understanding of why under sink water filters are great and what features to pay attention to when shopping.

About the author

Lisa Ward is the owner and main author of Sink and Faucet. She has a degree in marketing and a passion for home design and architecture. When she is not working, you might find her doing home improvements at her own house, reading, or flipping through home design magazines at her favorite coffee house.