Best Under-Sink Water Filters

Updated September 2019
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BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We may earn a commission if you purchase a product through our links.
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.
We may earn a commission if you purchase a product through our links.
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How we decided

We purchase every product we review with our own funds — we never accept anything from product manufacturers.

25 Models Considered
6 Hours Researched
1 Experts Interviewed
102 Consumers Consulted
Zero products received from manufacturers.

We purchase every product we review with our own funds — we never accept anything from product manufacturers.

Why trust BestReviews?
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.
We may earn a commission if you purchase a product through our links.
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We may earn a commission if you purchase a product through our links.
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.
We may earn a commission if you purchase a product through our links.

Buying guide for best under-sink water filters

Last Updated September 2019

One of the best things you can do for your body is keep it hydrated. Unfortunately, there may be enough contaminants in your household tap water to make that practice less healthy than you desire. Purchasing an under-sink water filter, however, is an easy way to be sure that only the purest water possible is flowing from your tap.

You need to find an under-sink water filter that is small enough to fit under your sink, but you also need one that is designed to filter out the particular contaminants in your water. You want a high capacity system with a long-lasting filter that is easy to replace.

If you'd like to learn more about what to look for in an under-sink water filter along with some tips to help you meet your body's daily water requirements, keep reading. If, on the other hand, you are ready to buy, consider one of the quality models we've spotlighted in this guide.

Besides health issues, water filters are effective in removing particulates that can clog, damage, or reduce the efficiency of washers, sink aerators, and ice makers.

What you need from an under-sink water filter

The reason you need an under-sink water filter is to reduce or remove impurities, contaminants, and odors so your drinking water is clean and pleasant tasting. But not all under-sink water filters are the same — some are better at removing certain substances than others. In order to get the best under-sink water filter for your needs, get the one that is NSF (National Science Foundation) certified for removing the specific contaminants in your water. The most common types of filtration include:

  • Particulate filters: These filters remove or reduce larger particles of sediment, including rust, dirt, and sand which may find their way into your drinking water.

  • Activated carbon filters: Activated carbon filters remove contaminants such as lead and mercury through a chemical bonding process. They are also effective at removing chlorine tastes and odors.

  • Oxidation reduction (redox) filtration: This process uses an electrochemical reaction to reduce contaminants such as chlorine and heavy metals.

  • Ion-exchange filtration: Water softeners use this technology to replace undesirable ions with less harmful ones. Besides exchanging calcium and magnesium for sodium, the process can help reduce other contaminants such as zinc and copper.

  • Reverse osmosis (RO) filtration: Reverse osmosis forces water through a membrane that collects any contaminants that are larger than water molecules. This process is the best for removing contaminants, but it has a downside: it produces large amounts of waste water, 3 to 5 gallons for every single gallon of purified water.

  • Ultraviolet (UV) filtration: Ultraviolet light can remove some viruses and bacteria, which can make you sick, but it does not filter out particulates.
CAUTION

Water filters do not work with hot water (over 100ºF), so under-sink water filters need to be installed on your cold water line.

Other considerations

Filter life

An under-sink water filter should have an appreciable life span. One that lasts three months is what you get in the lowest price range, but you may find yourself slacking on keeping up with filter replacement. Since a filtration system is only effective if the filter is clean, you may want to consider a higher priced model that is longer lasting.

Ease of maintenance

Most under-sink water filters only require changing the filter. You want to purchase one that is easy to swap out so you don't put off changing the filter.

Dedicated faucet

Some under-sink water filters require you to install a dedicated faucet to dispense the filtered water. These models are a bit harder to install, but if you want the cleanest possible water, this is the way to go.

Size

Some under-sink water filters are very small and can easily fit beneath even the tiniest sink, while others have several filters and a tank. Be sure the system you are considering will actually fit in the space you have available.

Multi-stage

A multi-stage filtration system uses several methods to filter your water. These are the most thorough systems, since each type of filter is best suited to reduce or remove a particular contaminant. However, they cost more.

Infused minerals

Some filtration systems have a stage that adds beneficial minerals to your water, if it’s desirable.

Water pressure

Low water pressure is good and bad. It’s good because it allows your filters to better reduce contaminants. Having a filter that drastically affects water pressure, however, can be frustrating — it can be annoying waiting for water to slowly fill a single glass.

Waste

Waste is a concern with reverse osmosis systems, as these systems can waste up to five times as much water as you purify. If sending five gallons of water down the drain for every one gallon you consume is troublesome, look for a reverse osmosis system with reduced waste.

Warranty

The best way to get a snapshot of the manufacturer's faith in their product is to review the warranty. Longer warranties quickly reveal the best under-sink water filters.

EXPERT TIP

Before purchasing an under-sink water filter, you need to know what’s in your water so you can purchase the product that will best filter it out.


Staff  | BestReviews

Under-sink water filter prices

Inexpensive: When shopping for an under-sink water filter, you can find models you install yourself which last up to 6 months for $40 or $50. As you move into the $60 to $100 range, you can find higher capacity models, which may last as long as three years.

Mid-range: Once you move to the $100 to $150 range, you find premium quality multi-stage under-sink water filters that remove a wider variety and greater percentage of contaminants.

Expensive: In the $150 to $250 price range, you find reverse osmosis filters that remove all harmful minerals from your drinking water accompanied by a multi-stage process that infuses your water with healthy minerals.

If you are not comfortable doing plumbing work, installation of an under-sink water filter may require the help of a professional.

Staff
BestReviews

10 tips for drinking more water

Water is only good for you if you actually drink it, and far too many people fall short of the recommended daily intake. To help ensure you get the most out of your under-sink water filter, here are a few tips to get you drinking more.

  • Start the day off right. Drink a big glass of water as soon as you wake up.

  • Track your glasses. Keep a running tally — either by hand or with an app — so you know exactly how much water you have consumed each day.

  • Use a smart cup. If counting is too tedious, purchase a cup that keeps track of your water for you.

  • Use a labeled water bottle. Some water bottles feature goal marks on them to give you consumption targets.

  • Fill it up immediately. The moment you finish your glass of water, fill it up again.

  • Drink on a schedule. Whether it’s a small glass at the top of every hour or an eight ounce glass every two hours, find what works best for you and stick with it.

  • Sip all day long. Instead of guzzling a whole glass at a time, sip your water consistently throughout the day.

  • Add water to your routine. Whether you drink a glass after using the bathroom or a bottle during exercise, tying a drink in with another activity can make it effortless to fulfill your daily water requirements.

  • Add some flavor. Spruce up your water intake by adding variety.

  • Use a carbonator. Sometimes, a little fizz is all it takes to get you excited about drinking water again.

Other products we considered

Frizzlife Quick Change Under-Sink Water Filter removes such contaminants as heavy metals, rust, mercury, lead, and odors, and it comes with a dedicated faucet. Nahla Pure Premium Under-Sink Water Filter is designed to last up to three years. The filter inserts into your cold water line and does not require a dedicated faucet. For those with a larger budget, iSpring 6-Stage Under-Sink Reverse Osmosis Drinking Water Filter System includes alkaline remineralization. This impressive system also serves as a water softener and can remove up to 99% of over 1,000 contaminants including arsenic, hormones, asbestos, calcium, bacteria, viruses, and more.

For an under-sink water filter to remain effective, you must replace the filter as instructed in the owner's manual.

FAQ

Q. What kinds of contaminants can be in water?
A
. You're probably familiar with the possibility of having lead in your drinking water, and some people are likely worried about excess fluoride or bacteria and parasites, but that's barely scratching the surface — a plethora of other contaminants can get into your drinking water. Chemicals and fertilizers used to spray crops, a multitude of minerals from natural deposits in the ground, and improperly disposed of pollutants can also wind up in our drinking water. Beyond that there are pharmaceuticals, personal care products, cleaning products, and even car emissions.

Q. How do I know which contaminants are in my water?
A.
Get it tested. It's as simple as that. Don't depend on your town's tests. These take place before the water enters your home, and there are many opportunities for additional contamination before the water comes out your faucet. You can purchase a drinking water testing kit and do it yourself or you can hire a service. The choice is yours, but until you test your water, you won't know what type of under-sink water filter you need to buy.

Q. How do I know if the filter I am considering will work for my water?
A
. The National Science Foundation (NSF) has a number of different standards regarding chlorine, hazardous contaminants, pesticides, pain medicine, plastics, detergents, and more. To be sure you are getting the best under-sink water filter for your needs, the water filter packaging needs to state that the filter meets the NSF certification for the particular substances you are concerned with.

The team that worked on this review
  • Allen
    Allen
    Writer
  • Devangana
    Devangana
    Web Producer
  • Eliza
    Eliza
    Production Manager
  • Kailey
    Kailey
    Writer
  • Katherine
    Katherine
    Editor
  • Melinda
    Melinda
    Web Producer

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