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Best Under Sink Water Filter

Best overall
Home Master TMAFC-ERP Under Sink Water Filter
5/5
Best Smart Filter
Waterdrop G3 Reverse Osmosis Water Filter System
5/5
Best Splurge
Clearly Filtered 3-Stage Kitchen Filter
5/5

Water filters have become the norm in most U.S. households. Despite the U.S. having strict regulations on water quality, most homeowners prefer to filter their water even further.

Additionally, not all households trust their state or city water. Recent news has brought numerous scandals related to water quality. Many of America’s cities have outdated pipes and some households are built in areas without public water. Numerous contaminants including hormones and even lead are a possibility in water.

Fortunately, there are many filtration systems that can be easily installed in your home, giving you more confidence in the water you drink. We have compiled a list of the top water filters to consider.

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The Best Under Sink Water Filters of 2021- Buyer's Guide

We compiled this list based on available features and customer reviews. Here are a few of our favorite under sink water filters:

1. Home Master TMAFC-ERP Under Sink Water Filter

Features

The Home Master TMAFC-ERP Artesian Full Contact Undersink Reverse Osmosis Water Filter System is a top-choice because of its long list of filtration features. This reverse osmosis system offers mineral water on tap using a patented demineralization process. It adds beneficial minerals back into the water, like calcium and magnesium, at two different points throughout the process.

 

The Home Master TMAFC-ERP Artesian Full Contact Undersink Reverse Osmosis Water Filter System is a top-choice because of its long list of filtration features. This reverse osmosis system offers mineral water on tap using a patented demineralization process. It adds beneficial minerals back into the water, like calcium and magnesium, at two different points throughout the process.

This water filter also reduces the level of wastewater, giving you more freshwater balance. The faster flow rate also means you can enjoy fresh water at the tap, without having to wait for it to filter.

Pros
Cons

2. iSpring RCC7AK Six-Stage Drinking Water Filter System

Features

This affordable iSpring Six-Stage filtration system uses a multiple-stage filtration process system that removes most water contaminants. It also uses a demineralization process that adds healthy minerals back. The system comes with everything you need to efficiently filter your water, including a lead-free brass faucet, which a lot of other systems don’t come with.

 

This affordable iSpring Six-Stage filtration system uses a multiple-stage filtration process system that removes most water contaminants. It also uses a demineralization process that adds healthy minerals back. The system comes with everything you need to efficiently filter your water, including a lead-free brass faucet, which a lot of other systems don’t come with.

iSpring also has a good reputation for customer service, meaning if you have any questions or concerns about your sink filtration system, you can easily reach out to them for assistance.

Pros
Cons

3. Waterdrop G3 Reverse Osmosis Water Filter System

Features

The Waterdrop G3 Reverse Osmosis Water Filter System is another good under counter water filter, mostly due to its cross filtration process.

The Waterdrop G3 Reverse Osmosis Water Filter System is another good under counter water filter, mostly due to its cross filtration process. This is another reverse osmosis system that prevents bacteria buildup in your water. Its smaller size also makes it ideal for those with less kitchen or under sink space available. The smart TDS monitoring panel means you can easily monitor filtration levels.

 

Pros
Cons

4. Claryum Direct Connect

Features

This Aquasana Claryum Direct product is on the best under sink list because of its convenient design and fast flowing filtration. This filtration system removes up to 15 times more contaminants than when compared to other reverse osmosis systems. It uses an innovative technology that uses four different filtering methods.

 

This Aquasana Claryum Direct product is on the best under sink list because of its convenient design and fast flowing filtration. This filtration system removes up to 15 times more contaminants than when compared to other reverse osmosis systems. It uses an innovative technology that uses four different filtering methods.

Installation is also easy, giving you instant access to clean water. Replacing the water filter is also easier than ever, without the need to disconnect any hoses or water lines.

Pros
Cons

5. Waterdrop WD-G3-W Under Sink RO System

Features

The Waterdrop WD-G3-W Under Sink RO System is on the best under sink water filter list because of its small size and ability to filter up to 400 gallons of water each day. This filter is also capable of removing up to 1,000 contaminants from your water, improving both the quality and overall taste of the water.

The Waterdrop WD-G3-W Under Sink RO System is on the best under sink water filter list because of its small size and ability to filter up to 400 gallons of water each day. This filter is also capable of removing up to 1,000 contaminants from your water, improving both the quality and overall taste of the water.

This sink water filter system also uses a reverse osmosis process that is slightly different than other filters. Whereas both types of systems use two components to filter, this one also has a tankless design. This means it takes up less space and offers a faster flow rating, directly filtering your water without wait time.

Pros
Cons

6. Clearly Filtered 3-Stage Kitchen Filter

Features

This filter, the Clearly Filtered 3-Stage Kitchen Filter, is another one of our favorite under sink systems because it removes the same contaminants as other under-sink systems, but also removes fluoride. Clearly Filter designed this under sink water filter with the goal of achieving a 100 percent filtration level. They use a proprietary Affinity Filtration Technology that removes up to 99.7 percent of over 232 contaminants.

This filter, the Clearly Filtered 3-Stage Kitchen Filter, is another one of our favorite under sink systems because it removes the same contaminants as other under-sink systems, but also removes fluoride. Clearly Filter designed this under sink water filter with the goal of achieving a 100 percent filtration level. They use a proprietary Affinity Filtration Technology that removes up to 99.7 percent of over 232 contaminants.

This undersink water filter uses multiple stages when filtering to remove a significant amount of contaminants, odors, and even fluoride. Stage one begins the process by removing contaminants and odors. Then, stage two removes heavy metals. Finally, stage three removes fluoride.

Pros
Cons

7. WaterChef U9000 Premium Under-Sink Water Filtration System

Features

The WaterChef U9000 Premium Under-Sink Water Filtration System is stylish and practical. It often makes it onto many best under sink water lists because of its innovative design and useful features.

The WaterChef U9000 Premium Under-Sink Water Filtration System is stylish and practical. It often makes it onto many best under sink water lists because of its innovative design and useful features. With features like intelligent monitoring and an NSF certification, this under-counter water filter is worth consideration.

Pros
Cons

8. APEC Top Tier Under Counter Water Filter System

Features

The APEC Top Tier Under Counter Water Filter System has a five-stage filtration process that has an impressive, 6,000-gallon capacity. It also has a good purification level of two and a half gallons per minute. This under sink filtration system is also really easy to install and doesn’t require any drilling or the use of a separate faucet.

The APEC Top Tier Under Counter Water Filter System has a five-stage filtration process that has an impressive, 6,000-gallon capacity. It also has a good purification level of two and a half gallons per minute. This under sink filtration system is also really easy to install and doesn’t require any drilling or the use of a separate faucet.

In fact, you can use an existing faucet to install this under counter filtration system, giving you ample access to a high-quality filtering process that improves your municipal water. The water filtration system effectively removes most harmful chemicals, including chlorine, lead, heavy metals, and even benzene contaminants.

Pros
Cons

9. M Aqua-Pure

Features

The 3M Aqua-Pure under sink filter uses three filters to remove heavy metals and other contaminants using the filter cartridge. This basic, entry-level sink water filter system effectively filters out two and a half gallons of water per minute. It also removes most contaminants, including chlorine, lead, benzene, and toxaphene.

The 3M Aqua-Pure under sink filter uses three filters to remove heavy metals and other contaminants using the filter cartridge. This basic, entry-level sink water filter system effectively filters out two and a half gallons of water per minute. It also removes most contaminants, including chlorine, lead, benzene, and toxaphene.

The filter used in this under sink water filter system is also NSF-certified. This means that it meets industry standards and you can be confident in the quality of the water you get.

Pros
Cons

10. Waterdrop Reverse Osmosis Water Filtration System

Features

The Waterdrop Reverse Osmosis Water Filtration System is our second Waterdrop under sink filter on our best of list. This RO system uses reverse osmosis with a tankless design to remove micro sediment membranes and other contaminants. Its design follows most traditional reverse osmosis systems, but with the addition of a tankless RO system.

 

The Waterdrop Reverse Osmosis Water Filtration System is our second Waterdrop under sink filter on our best of list. This RO system uses reverse osmosis with a tankless design to remove micro sediment membranes and other contaminants. Its design follows most traditional reverse osmosis systems, but with the addition of a tankless RO system.

You can expect excellent performance with this under sink filter. It uses composite filters that means you won’t have to replace the filter cartridge, or the filter itself, often. This tankless design also gives you more space, especially when compared to a countertop water filter. RO systems also remove most harmful contaminants, including sediment filter from your water, while maintaining healthy minerals.

Pros
Cons

What is an Under Sink Water Filter?

An under sink water filter allows you to filter your drinking water on demand by placing a unit underneath your sink. They are a point-of-use (POU) product, which means you install them right where you intend to use them. It filters the water directly, right at the faucet, providing you with clean drinking or cooking water.

How Does an Under Water Sink Filter Work?

Underwater sink filters work by filtering your water as you run it from the tap. An underwater sink filter can go in a cupboard under the sink, where it is off the counter. In most cases, you’ll hook the filter up to the cold water line, since this is your drinking water. The water line is then attached to the main supply for an even flow.

The filter is always on, so when you turn on the faucet, the water flows through it. In most cases, you can still use your hot and cold water lines as normal but only water that flows through the filter is filtered. Some under sink water filters use your cold water faucet, whereas others require a separate faucet.

You can install under-sink filters underneath any sink to filter out your tap water. This might include your kitchen or bathroom sink. If you want, you can even install it to your cold water supply in your basement or garage sink.

Do I Need an Under Sink Water Filter?

Although the United States does regulate water quality, this doesn’t mean that your local drinking water is free of all contaminants. The Clean Water Act is a federal law that was enacted in 1948 that regulates water pollution. The goal of this regulation is to restore and maintain the quality of United States drinking water.

Additionally, even if the water that comes from your local city is clean and completely free of contaminants, debris from your pipes or faucets can also make it into the water. The best way to understand your water and what’s in it is to have a professional water quality test completed. Older homes are more likely to have contaminants in their water, some of which are legal.

You generally have three options when it comes to filtering your water, including a countertop filter, an under water sink filter, or a whole house system. You can use filtered water for drinking or cooking.

EPA Rules and Regulations

Under sink systems have the purpose of filtering your water to make it taste better and so that it is safer to drink. The Environmental Protection Agency (EPA) is responsible for protecting humans and the environment. One of their duties is to manage the water quality association and monitor what contaminants are in U.S. drinking water.

The Safe Drinking Water Act

In addition to the above Clean Water Act of 1948, the EPA also enacted the Safe Drinking Water Act (SDWA) in 1974. The SDWA ensures the quality of American drinking water. They set quality standards that must be followed by local governments. Additionally, certain regulations may be set by states, localities, and even water suppliers. With numerous water scandals making the news recently, many Americans have come to worry about what is in their water.

Benefits of an Under Water Sink Filter

Under water sink filters offer the following benefits:

  • They take up less space than countertop filters.
  • They give you easy access to clean, filtered water right from your faucet.
  • They lead to less plastic waste as you don’t have to buy bottled water.
  • They can improve the taste of your water.

Also, some water filters use an active carbon process. This improves the taste of your water. An under water sink filter is a good idea for anyone who wants fresh, clean water.

Under sink filters are also affordable and fairly easy to install. Depending on the filter you choose, you may even be able to install it on an existing faucet.

What Contaminants Does an Under Sink Filtration System Remove?

One of the biggest benefits of installing an undersink water filter is to remove harmful contaminants from your drinking water. Under sink water filters can remove contaminants like:

  • Heavy metals
  • Lead
  • Chlorine
  • Sediment
  • Bacteria
  • Fluoride
  • Benzene
  • Herbicides

This leaves you with purified water that tastes good and is odor-free. Additionally, some filtration systems have the ability to add minerals back into the water. This leaves you with filtered water that not only tastes good but is also better for you. One of the biggest problems with bottled water is that it often doesn’t include the necessary minerals.

How to Choose the Right Under Water Sink Filter

How do you decide which under water sink filter is right for you? There are a few things to consider when choosing:

Filter and Unit Size

You want to choose a filter size that fits your space. A smaller pitcher may be acceptable in a single-use household. However, households with larger families may need a larger filter with greater capacity. You want to consider how much water your household uses each day. Size may also refer to the actual size of the unit. Consider how much space you have under the sink when choosing the right unit.

Types of filtration Available

Many water filters offer different types of filtration. Reverse osmosis used to be your only option when it came to under sink filters. You have more options today with the use of different filters. Here are a few filter types to consider:

Carbon Filter

A carbon filter is newer but has quickly become one of the most popular choices. Carbon filters include an activated carbon filter that improves odor and taste. An activated carbon filter is also capable of removing larger contaminants from your tap water. This includes silt and sediments. The carbon filter works by absorbing these larger contaminants and removing them.

Reverse Osmosis

Reverse osmosis was once one of the most common types of under sink filters initially. It does a good job of removing harmful contaminants and odors, and proving you with clean drinking water. RO systems also do a good job at removing heavy metals without affecting the water pressure of the existing sink.

Alkaline

Alkaline filters use a process of electrolysis. When filtering, the water goes through electrically charged plates. The plates separate the water into two different streams, one that’s acidic, and another that’s alkaline. In some cases, an alkaline filter can be added to an under sink filter, especially if you prefer a certain taste of water. An alkaline filter also adds good minerals like calcium and magnesium.

A lot goes into choosing the right filter for your needs. The good thing is that regardless of which filter type you choose, an under sink water filter can significantly improve the quality of your water.

Water flow

Different water filters offer different flow levels. This refers to how fast the water comes out of the faucet after it’s filtered. If the filter has more levels, then it usually flows faster. The flow rate is calculated by considering the gallons per minute. The average flow rate is between 0.8-2.0 GPM. If you and your household use a lot of water daily, then you may need a unit with a faster water flow rate.

Odor removal

Some water filter systems also have the ability to remove odors. The EPA estimates that up to half of U.S. tap water has an odor. This smell is usually from chlorine. One of the most common reasons for using a water filter is to remove this odor. It reminds you that there might be bacteria or parasites in your drinking water. The higher the level of filtration, the more likely it is to remove bacteria and odor.

Wastewater

Wastewater refers to the amount of water wasted during the filtration process. You ideally want a low waste to pure water ratio. Units that have higher amounts of wastewater may filter out more contaminants but also waste higher levels of water. This can lead to an increase in your household’s water use and even your water bills.

Water pressure

You also want to consider your home’s water pressure. Filters often require certain water pressure ratings to work. This specific number varies, depending on the unit, but the minimum is usually between 40-45 psi. If your water pressure is too low for the unit, then it won’t be able to filter the water properly.

Type of faucet

Your home’s faucet can also make a difference. Check that your sink and faucet are compatible with your filter. Some units also require the use of a separate faucet, whereas some allow you to hook it directly to the existing faucet and cold water line. If you don’t have room for a separate faucet, then you may need to consider an undersink water filter that uses your existing faucet.

Contaminants removed

One of the main goals of an under sink water filter is to remove contaminants. When choosing the best under sink filter, you want to choose one that removes the types of contaminants you have in your home. You can learn more about your household’s needs by scheduling a water quality test before choosing the right unit.

Filter life

Different filters have different life spans. If you want a unit with minimal maintenance, then choose one with a higher filtration level before replacement. Under water sink filters list their filter life, so you can get a better idea of how often you will have to replace each one.

Minerals added

Some under sink water filters not only remove contaminants but also add minerals. This can make your water taste better.

Price

Price may be an important consideration when choosing the right filtration system. While you don’t want to aim for the cheapest, you do want to choose a sink filtration system within your budget.

Available Features

Different filtration systems also come with varying features. Automatic flushing, for example, can extend the life of your filter. It does this by automatically flushing the lines which can reduce clogs and improve the overall quality of the filtration systems.

Another popular feature that is often available in Waterdrop filtration systems is holiday mode. In holiday mode, the system continues flushing when it’s not in use for more than 24 hours. This prevents a buildup of contaminants, which could also block your unit. An overworked reminder also informs you when your filter needs to take a break. This gives the unit time to recharge and cool off.

Some filtration systems also have the ability to notify you when it is only intermittently working. If the unit is constantly turning on and off, it may mean that your water quality is not as good as it could be.

Installation

The installation process is also important to consider. Some under sink filters are easier to install, whereas other may provide better-purified water, but may require a professional plumber. One of the biggest differences when it comes to the installation process is determining if you need to add an additional faucet, or if you have to affect the cold water supply line.

Some sink filters require you to connect directly to the water supply. Keep in mind, this may make installation easier, but can also affect the water pressure. Of course, you also want to choose a water filter that you are capable of installing. You may also choose a different one if you plan on hiring a plumber to install it.

You can learn a lot from sink water filter reviews. Specifically pay attention to what users liked, and didn’t like, with different RO systems. For example, some may have a shorter-than-average filter life, which means you have to change them more often. Sink water filter reviews can also help you decide if an underwater filter is right for you, or if you’d prefer another type, like countertop water filters.

How to Install an Underwater Sink Filter

Installing an underwater sink filter is simple but does require some basic plumbing knowledge. As long as your sink already has a separate hole available, in addition to the faucet, then the installation should be easy. Some kitchens may have existing holes for other kitchen features like a soap dispenser or another faucet. If you’re not using these, you could easily remove them to then install the sink filter.

You can easily install your under sink water filter with the following steps:

  1. Turn off the cold water supply: You will need to first turn off the cold water supply before beginning installation. Open the faucet and release any leftover cold water supply.
  2. Connect the filter adapter: Connect the adapter with the hose included in the kit. It should indicate which pipe connects to which tube. Connect both adapters to it.
  3. Turn the water back on: Once all hoses are connected properly, turn the water back on.
  4. Test the water: Let the water run for 5-10 minutes to activate the filter. Be sure to check things like the water pressure or that the water supply is working properly.

Keep in mind, this process may differ depending on the type of water filter you choose. If you’re not confident in your installation abilities, consider working with a professional plumber.

Modern Filter Systems Vs. Reverse Osmosis: Which Type is Better?

All water filters once used a reverse osmosis process. This included an electrically charged plate that filtered the water using these charges. Reverse osmosis refers to a filter that is typically difficult to install. This is because the filter itself also often includes numerous layers of filters.

This also means that the actual filtering of the water takes longer. The typical timeline of filtering water using a reverse osmosis process can be up to two hours.

Today’s water filters use different processes. One of these is an activated carbon that reduces chlorine and chloramine. The alkaline in the filters absorbs the larger contaminants in the water. This gives you a better quality of water that is also faster to filter.

You will find under water filter systems that use many different types of filters. Some of these use RO systems, whereas others don’t.

Frequently Asked Questions

The specific filter that you choose will determine how much space it uses. Some units take up more space than others do. If you are limited on space, it may be best to choose a compact water supply.

Some homeowners choose to remove an existing soap dispenser or handheld sprayer to install the filter. However, regardless of which one you choose, the filter does take up some space. When ordering your new under sink water filter, always measure the space first. In addition to choosing a unit that fits your space, you also need to leave enough room to change the filter or clean it as needed.

Some households may choose to filter their water with a pitcher filter. You can buy pitcher filters in most stores and they are often affordable. However, they don’t have as much capacity. They also tend to not last as long. If your household uses a lot of filtered water, then it may be best to go with an underwater sink filter.

Additionally, while it may seem like a pitcher filter is always the better financial choice, this may not be the case if you’re having to replace it frequently. While an underwater sink filter will cost you more up-front, you will eventually save by not having to change out the filters often. Pitcher filters usually filter less water than even counter filters.

Another common way to filter household water is with a countertop water filter system. Countertop water filters tend to be more affordable and easier to install. They are portable and don’t take up any under sink space. However, they do take up valuable counter space. Countertop water filters also can only filter a small amount of water, usually the same size as the filter itself.

If you want a more permanent solution to water quality, then an under sink water filter is your best and most cost-efficient option. RO systems effectively remove sediment filters, heavy metals, and other contaminants. They offer purified water on demand, simply by turning on your faucet. While the installation process of an under water system may be more in-depth than a countertop filter, it offers better results

Another option that you have when it comes to filtering your water is to have a whole house filtration system installed. Because a whole house water filter filters your entire house’s water supply, it is usually much costlier to install. Additionally, installation is much more time-consuming and often requires plumbing knowledge. In fact, if you choose a whole house water filter, you will likely need a professional to install it.

In most cases, you don’t need a whole house water filtration system unless your home is subject to larger contaminants, like sand or iron. Most professionals recommend an under sink water filter system for any other type of contaminants. An underwater sink filter is effective in removing most other types of contaminants.

Whether you are considering an under sink water filter, or you already have one, you may want to know what your current water quality levels are. There are a few ways that you can learn more about what’s in your water.

For one, you can review previous and current water assessments provided to you by the EPA. You can also test your own water. You may decide to purchase your own test kit or hire a professional. If you decide to test your own water, the process is simple.

You can collect a few samples at home and then send them to a licensed lab. From here, they will send you a report that informs you not only of what items are in your water but where they fall within the required range. This report is often surprising to homeowners as they learn that some degree of contaminants is allowed in your water.

Even if your test comes back satisfactory, you should routinely test. It is best to repeat testing anytime your water conditions change. This might include when a new well is installed, or if you notice any differences in your water. If anyone in your household becomes pregnant, or you have a new baby in the household, it may be worth it to test again. Babies often have a lower threshold for water quality.

There are many factors that go into the cost of an under cabinet water filter system. Whole-home systems can cost anywhere between $300-$1,000. Reverse osmosis systems can range in pricing between $150-$500.

An under sink system can cost between $50-$400. Finally, a countertop system can range anywhere between $50-$120. However, in addition to the cost of the installation process, it is also important to consider replacement filter costs. While a countertop system may be the cheapest, it doesn’t filter as much water. You’re also more likely to spend more on changing the filter.

When you opt for a better system, like under the sink systems, you will likely have to replace the filter less often.

When considering the cost of an under water filter system, it can also be beneficial to evaluate your cost savings. Many households rely on bottled or jugged water for drinking water. Once you install an under water filter system, you can get rid of this cost.

It can take between a couple of minutes to a couple of hours to install an under water sink filter. This depends on the type of filter you buy and how comfortable you are with installing basic water filters. If the water filter that you choose has a separate water dispenser, it may be a little more difficult to install. The good thing is that once you choose a filter, most come with tutorials that can help with installation.

Whether or not you need to call a plumber will depend on your comfort level. Some people may feel that they have the skills necessary to install their under sink filter, whereas others are more comfortable calling a professional.

Even if you choose to install your filter on your own, know when to call in a plumber. For example, if your water filter begins to leak, it’s best to have it checked out.

Once you have installed your under water filter, it’s important to keep up with maintenance. This will ensure that you have fresh, quality water and that your system lasts as long as possible.

You can maintain your filter with the following tips:

  • Know how often to change your filters: The type of system and filter that you have will determine how often you need to change your filters. Modern sentiment and carbon filters will need to be changed more often. Additionally, if your home has well water, you should also change your filters more often.
  • Follow the specific instructions of your undersink water filter: Regardless of which reverse osmosis filter you choose, you should carefully follow the directions. This ensures that it’s installed properly, which can help to maintain its quality.
  • Know when to adjust the tank pressure: If your system comes with a tank, you may need to adjust its pressure from time to time. Frequently review the tank’s pressure gauge and add, or remove, air as needed.
  • Check the durability of the O-rings: Some professionals recommend changing your O-rings at least once a year. This ensures that they seal your unit well.

Routine maintenance ensures that your unit continues filtering water properly. It can also help with reducing replacement filter or unit costs, which can get costly.

By now, you should have a good idea of the top undersink water filters and which one is right for your household. You can learn more about your water quality by conducting a home test. This gives you a good idea of which unit is best for you. Today’s units also come with many beneficial features that can provide you with fresh, healthy drinking water.

Dino Paccino

Dino Paccino

Dino is a lifelong writer and home improvement specialist. He enjoys bringing cutting-edge information on home renovation and remodeling to Kitchen Infinity.

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