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The Best Under-Sink Water Filters for Great-Tasting H2O Right From the Tap

The best in performance and convenience.

7 of the Best Under-Sink Water Filters of 2023

Real Simple / Marcus Millan

For drinking water that’s clean and tastes better than bottled water, an under-sink water filter should be on your shopping list. Compared to other filters (like countertop and pitcher filters), they remove more contaminants from your water supply. Though under-sink filters require a few extra steps to set up, it’ll be a worthwhile effort that will result in free-flowing water that’s safe and delicious to drink. 

But what makes under-sink filters good? Zachary Rice, president of water filter company Multipure, says that if you want clean water, under-sink water filters should be your number one option. “Pitcher filters operate by gravity flow and typically use granulated carbon to improve taste, but performance is limited and you have to wait a few minutes for the water to flow through the filter,” he says. “Faucet-mount filters offer slightly better performance, but the cartridge is relatively small as it has to fit at the end of the faucet, so filter changes are frequent and more expensive.” 

Under-sink water filters, however, combine the best in performance and maintenance. “The water is dispensed through a designated faucet on the counter, offering immediate drinking water that is often healthier and more economical than any other option,” Rice says. “They use larger cartridges, feature more technology, and have higher performance.” Plus, they’re out of sight to free up counter and refrigerator space.

In addition to Rice, we spoke to Mark Gillece, founder, and general manager at Mark Allen PHC, for additional expert insight on what you need to look for when choosing an under-sink water filter for your home.

Best Overall

Aquasana Claryum 3-Stage Under-Sink Water Filter

Amazon Aquasana Claryum 3-Stage Max Flow

Amazon

What Stands Out
  • It’s NSF-certified and can remove 78 contaminants from your drinking water.

What Could Be Improved
  • Installation requires you to drill a hole in your sink or counter.

This model from Aquasana features a three-stage filtration system, which includes a pre-sediment filter that rids your water of sediment, silt, and rust, and two carbon filters that reduce pesticides and chemicals (commonly found in well water) and asbestos, chlorine, and mercury. Specifically, it removes 97% of chlorine and chloramine; 99% of microplastics, cysts, lead, and volatile organic chemicals (VOCs); and 95% of mercury, while selectively retaining beneficial minerals your body needs, including calcium and magnesium. 

Depending on how much water you drink, the filter should last about six months or 800 gallons—whichever comes first.. On top of that, the zero-waste filter system ensures that you get to keep all the water coming through the reverse osmosis design. 

When it comes to installation, you don’t have to disconnect water lines or hoses. However, you will need to drill a half-inch-diameter hole in your sink or countertop to accommodate the tubing and the metal faucet, which is included with the filter.

Filter Type: Carbon | Filter Capacity: 800 gallons | Certifications: NSF/ANSI 42, 53, 401 + P473 certified

Best Budget

Waterdrop 15UA Under-Sink Water Filter

Amazon Waterdrop 15UA Under Sink Water Filter System

Amazon

What Stands Out
  • It has a 16,000-gallon water capacity.

What Could Be Improved
  • You can only connect it to cold water lines.

The Waterdrop WD-15UA wowed us with its long two-year lifespan and 16,000-gallon water capacity. Its advanced filter membrane prevents particles larger than 0.5 micrometers from going through to your water. As an NSF/ANSI 42-certified water filter, the Waterdrop meets the highest water filtration standards and ensures that contaminants like sediment, heavy metals, and chlorine will not show up in your drinking water while effectively retaining healthy minerals that your body needs.

The product itself also comes with double rubber baskets (most filters only have one) to ensure a tightly sealed water valve and prevent leaking. In addition to connecting it to your regular kitchen faucet, you can also hook it up to your fridge to make filtered ice cubes, or to your bathroom sink. Its compact size makes it a good choice for RV use, as well.

Although this particular model produces 16,000 gallons of filtered water, Waterdrop also carries an 8,000-gallon and 24,000-gallon capacity in the same line (WD-10UA and WD-17UA, respectively). We really like that the filter refill is less than half the price of the filter itself, so it isn’t expensive to replace. It’s worth noting though that you can only connect this water filter to cold water lines only.

Filter Type: Carbon | Filter Capacity: 16,000 gallons | Certifications: NSF/ANSI 42

Best Reverse Osmosis

iSpring 6-Stage Reverse Osmosis System

Amazon iSpring RCC7AK 6-Stage Under Sink Reverse Osmosis Water Filter System

Amazon

What Stands Out
  • The triple sediment filter removes 99% of contaminants in your tap water.

What Could Be Improved
  • Installation may require plumbing experience and/or professional help.

The iSpring RCC7AK 6-Stage Reverse Osmosis System With Alkaline Filter offers a reverse osmosis six-stage filtration system, designed with a semi-permeable membrane and a triple-layer sediment filter to remove 99% of over 1,000 chemicals like nitrates, chlorine, asbestos, and calcium from your tap water. It also reduces levels of TDS (Total Dissolved Solids), which include harmful contaminants like sulfate, bromide, and arsenic. An alkaline filter also adds healthy minerals back into your water for natural-tasting and odor-free water—up to 75 gallons of it a day. 

Note that this system comes with a storage tank, so you’ll have an extra water reservoir in case of an emergency. We also appreciate that iSpring throws in a solid brass faucet for you to connect to your system. Because its filters tend to wear down and absorb fewer toxins over time, you should aim to replace them every six to 12 months. Although the system comes with instructional videos and lifetime technical support, it may be hard to install it yourself if you don’t have any plumbing experience. 

Filter Type: Reverse osmosis | Filter Capacity: Replace every 6 or 12 months | Certifications: NSF 58/ANSI

Best for Well Water

APEC Water Systems Essence 5-Stage Reverse Osmosis Water Filter System

Amazon APEC Water Systems ROES-50 Essence Premium Quality 5-Stage Under-Sink Reverse Osmosis Drinking Water Filter System

Amazon

What Stands Out
  • It has a 50-gallon per day capacity suitable for up to a four-member household.

What Could Be Improved
  • It comes with a 4-gallon tank, so you need to have a large space under your sink to keep it.

The Essence Premium Quality 5-Stage Under-Sink Water Filter System consists of several large-capacity carbon block filters that last up to one year. The five-filter system starts by removing sediments, followed by two steps of carbon block filters to remove chlorine and any tastes and odors. Then, a fourth filter removes chemical contaminants, and finally, a coconut filter gets rid of any remaining taste.

The system removes 99% of impurities like lead, chlorine, and iron to name a few, making it especially great for those using well water. It’s also World Quality Association Gold Seal Certified, which means it has undergone rigorous testing (and annual retesting) to ensure that it is safe for household use and meets the requirements for reducing levels of contamination as stated by the company. 

It also has a 50-gallon per day capacity, making it a good size if you're in a three or four-person household. You’ll also get a free faucet that comes with the system for easy, convenient access to your newly filtered water. Keep in mind that this APEC is not tankless, so you want to make sure you have enough storage to fit the filters and storage tank.

Filter Type: Reverse osmosis | Filter Capacity: Replace every 12 months | Certifications: WQA Std 58 Gold Seal Certified

Easiest to Install

Kraus Purita 2-Stage Water Filtration System

Amazon Kraus Purita 2-Stage Under Sink Water Filtration System with Digital Display Monitor

Amazon

What Stands Out
  • You don't need to drill a hole in your counter to set it up, and it comes with all the mounting hardware.

What Could Be Improved
  • It does not filter TDS from your tap water.

For a water filter with easy-to-follow instructions for installation, the Kraus Purita 2-Stage Water Filter System is an ideal option. It uses a two-stage filter system that has carbon block filters to remove heavy metals, VOCs, chlorine odors, and tastes from your water. It also has a polypropylene filter that can stop sediment, rust, and dirt from sullying your water.

The size alone snugly fits under your sink without bulky accessories or hardware. With the Kraus, you get all the mounting hardware you need to install, including batteries, tubing, and adaptors. The cartridges have a twist and quarter-turn lock mechanism, so whether you're doing the initial installment or replacing the filter, you can easily DIY it in minutes. To help you monitor, there is a screen on the housing which shows the filter status, and battery life and delivers reports on water quality.

Generally, you’ll need to replace the cartridge after 700 gallons or six months. Other than the fact that it won’t remove TDS from your water, we still think it offers comprehensive filtration at an affordable price.

Filter Type: Carbon | Filter Capacity: 700 gallons | Certifications: IAPMO for NSF/ANSI 53, NSF/ANSI 401, NSF/ANSI 42, NSF-372, CEC, PFAS

Best Long-Lasting Filter

CuZn UC-200 Series Under Counter Water Filter

Amazon CuZn UC-200 Under Counter Water Filter

Amazon

What Stands Out
  • This water filter is the only one on our list with a five-year lifespan.

What Could Be Improved
  • You have to replace the entire system, not just the filter, and it can't be used with well water.

The five-year guaranteed lifespan of the CuZn UC-200 is hard to beat, making it an ideal choice for those with big families that consume a lot of water. The catch is that after five years you’ll have to replace the entire system and not just get a replacement filter. The UC-200 has a three-stage filtration system that features a micro-sediment membrane to screen out sand and other particles, a coconut shell-activated carbon filter to remove pesticides and nasty odors from the water, plus a bacteriostatic filter that prevents bacteria growth and gets rid of heavy metals and lead. Keep in mind this filter is only designed to purify city water systems and cannot be used with well water.

If you find that your CuZn UC-200 needs to be replaced before the five years are up, the company will replace it for free under the product’s warranty. Installation is simple, and the company also provides video tutorial instructions on its website. You won’t have to drill a hole in your sink, either. 

Filter Type: Carbon | Filter Capacity: 50,000 gallons

Final Verdict

Our top pick is the Aquasana Claryum 3-Stage Under-Sink Water Filter for its three-stage filtration system that removes 99% of all contaminants from your drinking water. If you want a less expensive option, the Waterdrop 15UA Under-Sink Water Filter has 8,000-, 16,000-, and 24,000-gallon capacity options that cost under $100.

How to Shop for Under-Sink Water Filters Like a Pro

Filter Type

There are a few common filter types you'll find in water filter systems.

  • Carbon Filter: A carbon filter is the most basic option when it comes to filtration, but it's still very effective. Activated carbon chemically bonds with contaminants, removing them as water flows through the filter. However, all carbon filters aren’t created equal, so the effectiveness of a carbon filter alone will vary. You should look for the level of filtration noted on the product, including the contaminants it will remove.
  • Reverse Osmosis Filter: The most heavy-duty option, reverse osmosis systems flush contaminants from the water supply to deliver filtered water through a separate faucet. The system works by pushing water through a membrane with pores that are incredibly small, so that only water molecules can pass through. That makes reverse osmosis filters the most effective, with the ability to eliminate thousands of toxins such as chlorine, fluoride, and heavy metals, as well as bacteria and pesticides. However, many take up a considerable amount of cabinet space and are pretty difficult to install, which means you’re better off relying on a professional.
  • Ultrafiltration: Ultrafiltration uses a hollow fiber membrane to stop debris and contaminants from entering the water. It’s not as effective as a reverse osmosis system, but it can preserve the healthy minerals that are eliminated in systems where only water molecules pass through. These systems are also easier to install, as they generally work as an addition to the existing faucet. However, in these cases, the filters will need to be changed much more often.

Gillece recommends reverse osmosis systems for filtering your water—and it’s the system he personally uses in his home. But everyone has different needs and requirements for what they want and need in their own home.

“When it comes down to it, it's not a one-size-fits-all scenario,” Gillece says. “Different scenarios require different filters and systems. And it never hurts to get your water tested, that way you know what’s flowing through the pipes and into your home.”

Installation

To install an under-sink water filter, you’ll need a few tools like a drill to make a hole in your sink for the faucet, a wrench, and a rag or small bucket to clean up leaks. Kits often come with detailed written (and some video) instructions for DIY installation. But if you need extra help, we recommend hiring a plumber or handyman to do it for you. 

General steps require shutting off your cold water line, disconnecting your cold water tubing, and replacing them with the new tubing and adapters that come with your new filter. Once everything is installed and you turn your water back on, it’s recommended to let the water run for five to 10 minutes before using it.

Certifications

According to Rice, certifications are important because they guarantee the quality of your filtration system. “[They] range from basic safety standards, which confirms the product is manufactured with approved materials, all the way to contaminant reduction testing, which confirms filtration performance against industry standards,” Rice says. “Only high-performance products will have a robust contaminant removal list on their certification.” 

Among water filters, the most common certifications are from the Water Quality Association (WQA) and the National Sanitation Foundation International (NSF). With both certifications, water filters must undergo rigorous initial product testing plus regular re-testing and site inspections in order to be certified. For example, a WQA certification is valid for three years, while NSF-certified products must go through re-testing and plant inspections annually. These certifications are not free, either; companies commit thousands of dollars to be renewed on a regular basis. This commitment ensures that customers are getting the best quality product that promises appropriate results. 

Questions You Might Ask

What are the benefits of an under-sink water filter?

Under-sink water filters are not as bulky as countertop or pitcher filters and feature a better design since they are tucked away under a sink. Of course, some filters (like those with large storage tanks) will take up more room than others. In that case, you might need to move around household items you keep under the sink to make room for your system. 

In addition to the aesthetics and improved counter space, under-sink water filters are generally more powerful and filter out more toxins compared to counter and pitcher water filters. In fact, many brands claim to remove up to 99% of harmful toxins like lead, chlorine, and sediment from the water. It’s much easier to access purified water since you only have to turn on the tap versus refilling water with a pitcher when it is empty. You can also expect a faster water flow since the filter is directly hooked to the water line. 

If you’re willing to pay for an upgrade, you can get an advanced under-sink water filter that can remove herbicides and pesticides from your water supply.

What contaminants do under-sink water filters remove?

Under-sink water filters are effective in removing a wide variety of contaminants like lead, mercury, chlorine, pesticides, sediments, and other heavy metals to name a few. Not all filters remove the same contaminants though, so make sure to look for one that is certified to remove whatever it is you don't want in your water anymore.

“For people in older homes or in older neighborhoods where older pipes are common, cast iron and ductile iron pipes can leach particulates into the water. It’s important to have filters that can remove them to make the water safer to drink and better tasting,” Gillece says.

How long do under-sink water filters last?

Depending on how many people are in your home and how much water you’re using, filters should be changed every six months to a year, according to Gillece. “When [the filter’s] time is up, you’ll probably start noticing a change in the taste of the water,” he says.

Most filters come with an indicator light that changes colors to show you when it needs to be changed. Green means the filter is ready to use. When it turns yellow, you’ll have to replace the filter soon. And when the indicator light turns red, it is time to get a new filter. Other filters use more advanced methods like a digital dashboard that shows the filter status on an LED screen (like the Kraus Purita 2-Stage Water Filter). They may also beep to let you know that it’s time to get a new one. 

Take Our Word for It

This article was written by Nor’adila Hepburn, a contributing writer for Real Simple. To put together this list, we researched the best under-sink water filters and compared filter types, installation, and certifications. We also spoke to Mark Gillece, founder and general manager at Mark Allen PHC in Pittsburgh, and Zachary Rice, president of Multipure, for expert advice on how to pick the right under-sink water filter for your home.

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Sources
Real Simple is committed to using high-quality, reputable sources, including peer-reviewed studies, to support the facts in our articles. Read our editorial guidelines to learn more about how we fact check our content for accuracy.
  1. Safe Drinking Water Foundation. TDS and pH.

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