Best Under Sink Water Filters: 2021’s Reviews

Waterdrop Filter System

Are you concerned about the quality of water you’re drinking? Does it have a bad or funny taste or smell? That’s a sign that you need a water filter. And not just any water filter. An under sink water filter is the most favorable kind. 

An under sink water filter is conveniently positioned so you can easily access it whenever you need clean water. This is due to a water line connection, which allows water to pass through the filter on its way to the faucet.

Other water filters include countertop filters and water pitcher filters; however, most people prefer using under sink water filters because of their simple design. They are easy to install, easy to maintain, and very convenient.

Best under sink water filters are effective at removing contaminants from water, making it safe for drinking. You may not need to purify all the water in the house, especially if it is clean. A water filter can be used for other household activities like laundry and other general cleanings.

Under sink water filters help you purify only the water you intend to drink. They remove foul odors and any other contaminants that may be in the water. These contaminants can be harmful to the body and cause illnesses.

Top 5 Under Sink Water Filters

  1. Waterdrop 3-Stage Ultra-Filtration System
  2. Aquasana 3-Stage Water Filter System
  3. Frizzlife 2-Stage Water Filter System
  4. CuZn UC-200 Water Filter System
  5. Clearly Filtered 3-Stage Water Filter System

As we stated earlier, under sink water filters are designed to remove contaminants from water, making it safe for human consumption. A good filter incorporates different materials that help to remove various types of contaminants.

For example:

  • Chlorine and chloramines, bad taste, and unpleasant odor – Under sink filters have an activated carbon layer that helps remove these contaminants.
  • Heavy metals like lead – An activated carbon filter with a small reinforcement of metal removal resin comes in handy here.
  • Arsenic and fluoride – These contaminants are trapped by an activated alumina cartridge reinforced with iron oxide resin.
  • Excess calcium and magnesium – A cartridge made from a cation resin helps remove these minerals that can be in excess and cause damage to the body.
  • Sediment particles like dirt – Trap sediments using polypropylene filters.
  • Bacteria and cysts – Use a sediment filter (made using sediment particles or sand) or one made of ceramic cartridges.

An under sink water filter can use the above-mentioned filters to help improve the taste of water. They also play a part in neutralizing the water and adding essential minerals to it.

We know how difficult it is to get quality under sink water filters in a market where there are so many. This article discusses the five best under sink water filters and guides you on choosing the best one to fit your needs. 

Best Under Sink Water Filters For the Money

Let’s discuss these systems in detail, looking at their features, how each one works, their pros and cons, and customer reviews.

1.   Waterdrop 3-Stage Ultra-Filtration System

Best Overall

The Waterdrop Ultra-Filtration under sink water filter is an innovative purification system that incorporates an all-in-one approach to purify water. It comfortably integrates into the waterway to prevent any leaks.

You can install and replace it easily without terminating the water supply. The water that is purified using this filter is of premium quality. The Waterdrop under sink water filter can trap up to 99.99% of the contaminants in water, including bacteria, chloramine, heavy metals, chlorine, and fluoride.

The manufacturer makes this under sink water filter in a simple design that allows you to do the installation without any complications. You can complete the installation in a matter of minutes. Consumers don’t have to worry about a faucet because the manufacturer adds it to the package, as a perk.


  • PP/UF/CT Filter Real-time Life Indicator – The indicating system shows the filter’s real-time status.
  • Filter Reset Button – This helps to reset the filter after replacing it.
  • Power Indicator – This water filter uses a battery to power the filtration process. The power indicator button tells you when you need to replace the battery.
  • PP Filter (Polypropylene filter) – Works effectively to remove the large particles and impurities from water.
  • UF Filter (Ultra-filtration filter) – Effectively removes most contaminants to ensure that the water is safe for use.
  • CT Filter – Improve water‘s taste and remove any foul odors.

The Waterdrop filter is made of semi-permeable, long-lasting membranes that can last up to 24 months. These membranes make up the different filters – PP filter, UF filter, and CT filter. After 24 months, the water filter alerts you with a changing light color. You can easily change the filters without cutting off the water. Reset the water filter using the filter reset button.

How it Works

The purification process takes place in three stages. 

Stage 1Water passes through the PP Filter, and all the large impurities are removed. These could be sediments of sand, silt, dirt, and other large particles present in the water. Suppose the water was looking dirty before passing through the PP filter. It will look clean once passing through the PP filter, due to the removal of large particles. 

Stage 2 – The water advances to the UF Filter, where most of the remaining contaminants are filtered out. The ultrafiltration membrane helps to desalinate the water, remove bacteria, and eliminate micro-organisms and other materials that affect the water‘s taste and odor.

Stage 3 – The purified water passes through the CT filter, where chlorine, fluorides, and heavy metals like lead are removed. It gives the water a good taste and removes any foul odors. At this point, the water is ready to drink.


  • The Waterdrop under sink water filter saves a lot of space under the sink due to its innovative horizontal design.
  • There’s no water wastage as this filter does not allow leaking. It has an integrated waterway design that ensures water doesn’t leak, even when changing filters.
  • It’s easy to install and use. You can do it yourself without any complications.
  • It’s durable and lasts long – The filters last up to 24 months before you can replace them.
  • It uses smart technology to indicate when it’s time to service the filters. The lights on the electronic indicators change, and therefore you know when to make changes.
  • It doesn’t make noise during the water purification process.


  • It’s expensive.
  • Three filters need replacement, making it a bit costly to maintain.

Customer Reviews

From the product’s official website, you can see that customers are happy with the product. Most of them are satisfied with the fast and easy DIY installation and its easy-to-use technology.

Click here to Get the Latest Deal on the Waterdrop Filter from the Official Site.

2.   Aquasana 3-Stage Water Filter System

Affordable Option

The Aquasana brand manufactures this under sink water filter as a solution for those looking to improve the quality of their drinking water. This water filter system prides itself on a purification rate of up to 99%, removing over 70 contaminants from the water.

Unlike other purifying systems that reduce the water flow rate, the Aquasana water filter ensures a high flow rate. This allows you to continue using water at the speed you are accustomed to.

The filters are designed to last up to 6 months. You can easily install it without the help of a plumber. The manufacturer also packages extra filters with your purchase.


  • Activated carbon – Eliminates contaminants like pharmaceutical drugs, herbicides, VOCs, pesticides, and MTBE.
  • Catalytic carbon – Targets elements of chlorine and chloramines, removing them from water.
  • Ion-exchange – Filters out heavy metals from water. The most common heavy metals present in water are lead and mercury.
  • Sub-micron Mechanical Filtration – Effectively captures chlorine-resistant cysts such as cryptosporidium, giardia, and asbestos.

How It Works

The Aquasana system incorporates a superior technology with a selective Claryum filtration that reduces over 77 contaminants. The process works efficiently to remove contaminants and maintain the required minerals in water.

The different filters help remove any contaminants present in water, and last for up to 6 months.


  • The filters can be replaced very easily because you don’t need to remove the hose pipes or any water lines.
  • Filters take longer to replace, giving value for money and making it very convenient for use.
  • It has a 20-micron pre-filter that captures dust, silt, and sediments that can clog the water filter system. This ensures that the filter lasts longer and can purify up to 600 gallons of water.
  • The Aquasana water filter has a smart alert system that sends you a warning when you need to replace the filters.
  • It has been tested by NSF and approved to filter and remove over 70 contaminants from water.
  • It retains the natural minerals in water, such as calcium and magnesium.
  • It uses Claryum technology for pure performance and excellent filtration.


  • The filters last for a shorter time (6 months) than other filters, which last for up to 24 months.
  • There are no replacements for some parts, like O-rings, in case they start to leak.

Customer Experience

Customers using the Aquasana are happy with its straightforward installation process. It has a rating of 4.5 out of 5 stars from over 1600 reviewers on the product’s official website.

Most of the customers recommend this product to other consumers because they are happy with its efficiency. However, some have complained about parts that cannot be replaced if the water filter starts to leak.

Click here to Get the Latest Deal on the Aquasana Water Filter from the Official Site.

3.   Frizzlife 2-Stage Water Filter System

Best Value

Frizzlife created this 2-stage water filter to clean water and remove up to 99.9% of contaminants like chlorine and lead, along with bad taste and foul odors. This system uses a replaceable filter cartridge. Instead of throwing away the whole part, you only change the inner filter.

Frizzlife’s filtration method incorporates a 2-in-1 technology with 0.5-micron accuracy. Even with this accuracy, the flow rate is maintained at 60 psi, which is fast enough to fill a 300ml cup in 3 seconds. This water filter system has undergone testing and certification to ensure its purification strength.


  • Auto shut-off design – Allows you to replace the filters without cutting off the water supply.
  • 3/8″ and ½” converter – Helps you choose which water line you want to use.
  • 2-in-1 advanced filters – Integrated to help remove contaminants up to 99.99%, as well as bad taste, odors, and turbidity.
  • FZ-2 Cartridge – This user cartridge allows you to change filters without throwing away the whole part.

How It Works

The Frizzlife system has one cartridge that is made by intertwining two cartridges. These two cartridges purify the water in two stages.

Stage 1 – It uses a sediment filter of 0.5-micron sizes to trap dust particles, sand, and silt. It ensures that the water is clean and with no colors.

Stage 2  – The Frizzlife uses a 0.5-micron carbon filter to remove any heavy metals, traces of chlorine and chloramines, VOCs, and other particles in the water.

These two stages purify and remove foul odors and tastes from the water, allowing you to enjoy every sip.


  • It’s economical and environment-friendly – you don’t have to throw away the whole plastic part while changing the filters; you need only to change the interior part.
  • It has a fast water flow rate – The Frizzlife does not reduce the amount of water, allowing it to run at a high flow rate of 60 psi.
  • It has an auto shut-off design that allows you to change the filters faster without cutting off the water.
  • It’s been certified for its capability to filter and provide quality water that is safe for drinking.
  • It’s cheap and affordable. The filters are not expensive during replacement, so you can get clean water continuously.
  • You can use it in multiple places, such as your refrigerator or ice maker using the IMC-2 ice maker.
  • The installation process is straightforward and effortless.
  • It saves space using a 2-in-1 technique, helping to reduce its size.


  • The hose connectors are not compatible with many water lines. It’s only compatible with 3/8″ and ½” sizes.
  • In some cases, it has been reported to reduce the water pressure.

Customer Experience

The Frizzlife has a rating of 4.9 out of 5 stars from over 300 customers who have used this product. They all praise it for its easy installation and the quick, uncomplicated changing system. This water filter uses very little space under the sink, and it doesn’t require a tank or electricity to keep it running.

Click here to Get the Latest Deal on the Frizzlife System from the Official Site.

4. CuZn UC-200 Water Filter System

This water filter is a high-capacity filter that is designed to purify municipal water only. If you are using well water domestically, this may not be a good choice. The CuZn UC-200 water filter system uses a 3-stage technology to purify water, and you can comfortably install it under your kitchen sink.

Its high capacity allows it to handle over 50,000 gallons of water. This system lasts up to five years. The CuZn UC-200 filtration system works effectively to remove organic and inorganic contaminants such as sediments, chlorine, cation heavy metals, pesticides, herbicides, algae, molds, odors, foul taste, and much more. It retains essential minerals, like calcium and magnesium, in water to improve the quality.


  • Micro sediment membranes – Used to filter out the sand particles, silt, and other undissolved particles.
  • Acid-washed coconut shell with activated carbon – Used to remove any odors and offensive tastes. It also targets organic contaminants like herbicides, chlorine, pesticides, THMs, etc.
  • KDF-55 Filtration media – Targets bacteria, cysts, and inorganic contaminants such as heavy metals.

How It Works

The water undergoes a 3-stage purification process to ensure that it’s well filtered. The CuZn UC-200 system uses a specially patented KDF-55 filtration media and activated carbon in acid-washed coconut shells to complete the filtration process.

These elements used for filtration are effective and purify the water while retaining essential calcium and magnesium elements that are useful in the body.

It only removes contaminants and retains calcium and magnesium; therefore, the water remains hard. It is not suitable if you are using well water for your household.

The CuZn under counter water purifier ensures that there’s no bacterial growth on the filters, thanks to its unique bacteriostatic system. This system discourages the growth of bacteria and molds.


  • It has a high capacity of up to 50,000 gallons.
  • It’s durable and can be in service for five years.
  • It removes all contaminants but retains important healthy minerals.
  • It’s very easy to install and use.


  • It is large and may not be very suitable for under sink areas with less space.
  • The manufacturer does not provide enough instruction on the installation process.

Customer Experience:

Customers are delighted using this water filter system because it is quick and easy to install.

Most customers using this water filter system recommend it to other people as they are extremely satisfied with their purchase.

Click here to Get the CuZn filtration system from Amazon.

5.   Clearly Filtered Water Filter System – 3-Stage 

The under sink water filter by Clearly Filtered provides high quality and good tasting water through its cutting edge technology for purification.

Even if you were to combine five of the best filters, they would not meet the quality of the purification done by this water filter. It has undergone testing by the NSF and has been proven to comply with NSF, EPA standards 42, 53, 244, 401, and 473.

The installation process is easy. You can use the under sink water filter by Clearly Filtered even if you are renting a house. And when it’s time to move to a new home, you can move with the water filter. It fits directly on the waterline, and you can do it yourself without calling a plumber.


The manufacturer has kept the exact make-up of this water filter a closely guarded secret; however, they ensure that all the materials used are safe and do not leach into the water.

Most consumers choose to use this product because of the many approvals from the NSF. It has passed third party testing, making it suitable for human use.

The under sink water filter by Clearly Filtered guarantees the removal of over 230 contaminants such as chlorine, fluoride, chloramine, heavy metals (arsenic, lead, chromium-6, and others), pathogens (E. coli, cryptosporidium, and others), pharmaceutical drugs, herbicides, organic compounds, and chemicals.

How It Works

The under sink water filter by Clearly Filtered incorporates a 3-stage purification process. Let’s look at each stage.

Stage 1 – This is where the granulated premium coconut carbon priming filter removes funny tastes, and eliminates chlorine, foul odors, and strange colors in the water. It works effectively to get rid of VOCs and any other chemicals present in water.

Stage 2 – The filter removes any heavy metals like lead, arsenic, and chromium present in the water. This is also where pesticides, herbicides, and other contaminants like radiation and PFAs are removed. These contaminants are removed up to 99.99%.

Stage 3 – This stage incorporates a fluoride and arsenic filter, which ensures that up to 99.5% of the fluoride is removed. This water filter uses unique technology to remove fluoride. The technology does not use activated alumina or bone char to complete fluoride removal.


  • The filters can last up to 15 months before you replace them.
  • You can install it quickly in about two minutes, and you don’t need to call the plumber.
  • The installation is not permanent, making it easy for you to travel with your water filter whenever you’re moving to a new house.
  • It’s designed to save space under your sink because of its slim size. It has a small depth of 3″, which allows it to occupy a tiny space under the sink.
  • The product is tested and approved for use by the NSF.
  • The company allows for a 30-day trial period.
  • Those in the United States enjoy free shipping.


  • It’s expensive to buy.
  • The replacement filters are sold at a high price.
  • There is a reduction in water pressure on the taps.

Customer Experience

Customers praise this filter’s design because of how well it fits under the sink. The water has an improved taste, so you enjoy drinking it. It can be easily installed, and customers love to do it themselves without calling the plumber.

This product has a review of 4.9 out of 5 stars from the customers who have used it. You can buy this product on the Clearly Filtered official website and other online retailers like Amazon.

Why Should You Use Under Sink Water Filters?

If you have been looking to purify your water, you might want to use an under sink water filter for your needs. Here are some of the reasons why under sink water filters could be an excellent choice for you.

1.   It Improves the Taste of Water

There are some contaminants like chlorine and sulfur that give water a horrible taste. You know it’s one thing to drink water and another thing to enjoy drinking the water. A good under sink water filter removes these contaminants and improves the water‘s taste.

2.   It Removes Contaminants and Makes Water Safe to Use

There are many contaminants in water. It depends on where you get your water from. Suppose you live in a town where there’s the provision of municipal water. In that case, you’ll only need to remove the contaminants left in the water after filtration by the municipal purification plant.

Those getting their water from rivers and wells could have more impurities present in their water. Some of these impurities are chlorine, chlorinates, heavy metals, bacteria, algae, herbicides, pesticides, dirt, rust, and silt.

Most under sink water filters have different layers of filters to remove all these contaminants and improve the safety, smell, and taste.

3. It’s Cost-Effective

Compared to bottled water, using an under sink water filter is far cheaper. The only cost you’ll incur is the buying price of the water filter. You’ll also need to replace filters once in a while.

A filtering system attached to your regular household water system will ensure that you enjoy drinking your water without worry. 

4.   It Saves on Space

You won’t need too much space to install a water filter because most of them can comfortably fit under your sink. If you use your under-sink area as a storage space for other things, you’ll only need to create enough room for the water filter.

Unlike other filtration systems that require a lot of space to install, this kind of water filter only requires a small space under the sink.

Under Sink Water Filter: Buying Guide

There are many types of under sink water filters available in the market. Most of them are sold online from these products’ official websites and other retailing online stores like Amazon.

You can also get some of these products from home improvement stores near you. However, most people prefer buying online because of the wider variety.

Before buying an under sink water filter, here are some things that you should consider.

They include:

The Type of Filter

You must take time to read the product’s specifications to see what type of filter the product is using. Some use filters that need replacement more often than others.

Others redirect the water to a different faucet and therefore come with its own faucet added to the package.

These different types of filters will determine the ease of installing the water filter. You might need to purchase one that you can install by yourself without having to call the plumber.


Check out the water filter measurements and compare them to the space under your sink to ensure that it will fit properly. Some under sink water filters have a larger size and might require more space than others.

Choose one that is likely to fit well. There are those designed to carry out the filtration process in a combined filter, minimizing the amount of space needed.

Ease of Installation


Most of these under sink water filters come partially assembled so that you can connect them quickly to the waterline. Others require further adjustments during installation. When choosing a water filter, consider the amount of work required to complete the installation.

A conventional water filter is much more complex to install. You might need the help of a plumber to complete the installation. In contrast, for an under sink filtration system, you can install it personally in a matter of minutes.

Cost of Installation and Maintenance

If you’re working with a budget, you’ll need to get a favorable water filter for your needs without breaking the bank. Conventional water filters are more expensive to buy and install because of the many parts that it comes with.

An under sink water filter is not costly, and you can install it by yourself. It is also easy to maintain as you only replace filters periodically. Good under sink water filters have a long working life and can remain in service for over six months.


These certifications are a mark of quality for water filters. They are tested and approved by NSF, ANSI, Water Quality Association, and others. These third-party institutions issue certifications for different water filters.

When choosing an under sink water filter for your needs, it is vital to check for certifications and any approvals from reputable institutions. You’ll be assured of the quality of the water you’re drinking.

Features You Should Look for in a Good Under Sink Water Filter

Filter Longevity

You don’t want to keep changing the filters constantly. Only purchase ones that can serve you longer before you replace them. High-quality cartridges have a longer filter life, giving you value for your money.

You can get this information from the manufacturer, but not all their claims are valid. It’s better to read through customer reviews and FAQs so that you can have relevant information according to what other people have said about the product.

High-Quality Lead-Free Faucet

Both conventional and under sink water filters require that you use a faucet that is compatible with its hose pipes. Most manufacturers package the fitting faucet together with the filter so that they are priced together.

Before buying a suitable filter for your home use, it’s important to consider the type of faucet usable with it and the material used to make it. Always ensure that it is lead-free because lead can easily dissolve in water, making it unsafe for use.

High-Quality Components

The components’ quality will determine how long the water filter will serve you and the water quality you’ll be drinking. When choosing a water filtration system, find one whose components are of the highest quality so that it can work effectively.

The most effective way to find out the product’s quality is to look at the customer evaluations on review sites. It helps you to get the correct information from those that have experienced it.

Efficient Installation Instructions

You’ll need to know how to properly install your water filtration system so that it can work effectively without leaking. For most under sink water filters, the manufacturers provide thorough instructions on how to install them.

They may also prepare an installation video online so that you can follow it step by step. For some manufacturers, when you visit their official website, you can have a chat with their customer support and get clarifications on the installation process.

Frequently Asked Questions About Water Filters

Where’s the Ideal Place to Install My Water Filter?

Under sink water filters are best installed under the sink. There’s a space under your sink where you store a few kitchen items. You can move the items and create some space for the water filter. They are packaged with a kitchen-design faucet, making them suitable for installation in the kitchen.

Do I Need to Call a Plumber to Install and Replace the Filters?

Many under sink water filters are easy to install, and you can do it yourself. The manufacturers are keen to provide enough information on the installation process to guide you in installing and replacing filters.

However, there’s no harm in calling the plumber if you feel inadequate for the job. You should also ask for help if you notice leaks after you have installed the filtration system. The goal is to have a stable filtration system in place for clean and safe drinking water.

Can I Test the Water to Know What Is in It?

Yes, you can test the water using a testing kit, especially if you are using well water. If you get your water from a municipal or any other supplier, contact them for information on the water they are supplying to you.

They’ll give you information on the source of the water, contaminants in the water, health effects that the contaminants can bring about, any purification process the water has undergone, and much more.

This kind of information is crucial as it helps you decide on the water filter to buy. A water testing kit can also help you get information on the contaminants present in the water.

Is a Water Softener the Same as a Water Filter?

No. A water softener only removes the elements such as calcium and magnesium that cause hardness in the water. A water filter removes other contaminants like bacteria, chlorine, heavy metals, chloramines, and sediments.

There are water filters that have water-softening features so that you can have clean and softened water. If you already have a water softener, you can consider buying a water filter that does not have a water softener as one of its features.

The choice of what water filter to buy will depend on the goals you’ve set for the quality of water you want. Calcium and magnesium are both important to the body, so you might want to have a water filter that retains them. This is up to you to decide.

Which Is Better: A Reverse Osmosis System or an Under-Counter Filtration System?

Each of these filtration systems has its advantages and disadvantages. For example, A reverse osmosis system removes more contaminants compared to an under sink filtration system. However, reverse osmosis filtration systems are very expensive and waste a lot of water, unlike under sink filtration systems that do not waste water and are affordable.

Is Electricity Needed to Power the Water Filter?

No. You’re not required to connect to an electricity source.

Conclusion: Is This Type of Water Filter Good for Your Home?

The quality of the water you drink will determine the quality of life you live. As they always say, “water is life.” Suppose you are looking to purchase a water filter that will meet your needs and give you quality water. In that case, you can consider some of the products we discussed in this review.

We have also pointed out some of the things you should look out for as you buy a water filter. It’s essential to check that list to get a quality under sink water filter to serve you effectively and last long.

Best Under Sink Water Filters: 2021’s Reviews