9/10

As compact as it is effective, the AO Smith Two-Stage Under Sink Carbon Filter is the perfect system for camping. The dedicated faucet and filter system installs in minutes thanks to the included tee and tubing—no plumber required. At just over five inches tall, it’s easily one of the most compact units on this list, making it ideal for use in small spaces like RVs and campers.

Pros

• Only five inches tall
• Faucet included
• Plumber-free installation
• Filter lasts for six months
• WQA tested and certified to NSF performance standards

Cons

• Best for families of up to four
• System will not reduce TDS

10/10

For large families or those who tend to forget to change out filters, a high-capacity filter is a must. The CuZn Under Counter Water Filter lasts up to five years per filter, meaning fewer replacements. A coconut shell carbon and micro sediment membrane ensures there’s fewer of the following contaminants: chlorine, disinfection by-products, herbicides, pesticides, sediment, water soluble cation heavy metals (lead, mercury, chromium VI, cadmium, etc), bad taste and odors.

In addition, it has a small enough profile that there’s still plenty of space to install an under-sink water heater next to it.

Pros

• Lasts up to five years per filter
• Made in the USA
• Doesn’t affect water pressure
• Simple to install
• Removes contaminants that affect taste and odor

Cons

• Does not soften water or remove TDS
• For use with municipal water sources, not well water

What to Consider When Buying an Under-Sink Water Filter

“When looking for any type of filter, we always recommend starting by checking your local water quality report to find out which, if any, contaminants may be present in your area. As part of the EPA’s Safe Drinking Water Act, all U.S. water suppliers are required to send out an annual report that tells you where your water comes from and what’s in it,” says Mellencamp. “Next, always look for a filtration system that has been independently tested and certified to NSF/ANSI or IAPMO standards to address the contaminants you’re concerned about.”

In order to select the best under-sink water filter for you, consider the different types of filtration available. There are many variations of water filters. Basic carbon options work by binding to contaminants as the water flows through. Reverse osmosis units force water through a semipermeable membrane that captures even smaller compounds and impurities.

If you have a large family or use a lot of water for cooking and drinking, make sure you take the flow rate into account as well. This metric should clearly state gallons per minute (GPM). You should also ensure the unit you’re considering will fit under your sink. Also, if you plan to install it yourself, make sure it doesn’t require any DIY methods that are outside your expertise.

How We Found the Best Under-Sink Water Filters

At Family Handyman, we’re always looking to help homeowners and DIYers make the right purchase for their specific needs. We analyzed over 20 top-selling under sink water filters before narrowing our list down to the 15 filters with the best ratings. From there, we combed through hundreds of reviews, looking for real accounts of how each filter performed for DIYers both experienced and inexperienced. This rigorous research led us to the final filters, with those top 10 making our official list.

FAQ

Are under-sink water filters worth it?

“We conduct a national consumer survey each year and our recent fifth annual Water Quality Survey found that concern over drinking water quality in the U.S. has more than doubled over the past two years with seven in 10 Americans expressing worry about the quality of their drinking water at home,” says Mellencamp. “Now, 91% of Americans filter their drinking water at home. It’s no wonder, considering an estimated 45% of the nation’s tap water contains the ‘forever chemicals’ known as PFAS and the EPA recently reported that almost a tenth of the nation’s drinking water service lines contain lead.”

If you consume more than a few gallons of tap water a day and you can afford one, an under-sink water filter is probably worth it. “Instead of having to constantly refill a pitcher and wait for water to drip through, under sink filters allow you to instantly enjoy clean water straight from the tap without waiting or taking up valuable counter or fridge space,” notes Mellencamp.

Once installed, they do most of the work and, until it’s time to replace the filter, are generally low-maintenance. On the other hand, if you don’t drink that much water or if you’re a renter, a pitcher or faucet-mounted filter could be a more practical option.

How long do under-sink water filters last?

The lifespan of an under-sink water filter cartridge can vary from six months to multiple years. The lifetime depends on the size of the unit, as well as the quantity of water processed. “Filtration elements need to be replaced at some regular frequency, usually every six months,” notes Mellencamp. “If the filters are not replaced and contaminants accumulate in the system, the water gets blocked over time. This creates two issues with water filters: 1) the water flow can slow and 2) the water pressure in the system can increase which puts stress on the system and can cause it to fail faster.”

How do you change an under-sink water filter?

The best under-sink water filters make changing out their filters and cartridges a straightforward process. However, some are easier than others. “You can typically rotate the filters out of the unit and pull them out. Then you install the new filters by rotating them into the filter. Many systems have automatic shutoff valves that turn the water off as you rotate,” says Mellencamp. However, not all do. Some multi-stage units may require you to shut off the water supply and use a housing wrench to access the spent cartridge.

Why You Should Trust Us

I’m a freelance writer who specializes in the home improvement, DIY and appliance space. Having spent more than five years as a residential and commercial carpenter in NYC–specializing in custom furniture construction and installation–I use my hands-on experience and expert insight to craft product reviews, buying guides and how-to articles. I’ve previously written for CNN Underscored, Business Insider and Popular Mechanics, in addition to Family Handyman.

Emily Way is an associate shopping editor for Family Handyman with experience researching products and recommending the best designs to consumers. She researched and updated this piece. Way consulted Derek Mellencamp, the General Manager at Aquasana and a leading national water filtration expert. Derek Mellencamp joined Aquasana in April of 2010 and is responsible for leading the Aquasana marketing efforts from product management to branding.