The Best Under-Sink Water Filters for Cleaner, Better-Tasting Water
The out-of-sight devices are the most convenient way to treat your drinking water.
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I’ve been testing water filters for more than 25 years, so when it came time to choose a system for my own home, the decision was a no-brainer: an under-sink water filter. Tucked neatly inside the cabinet, it stays out of sight while a small dispenser next to my main faucet serves up clean, delicious water with a simple turn of the knob.
Our top picks:
- Best overall: Aquasana 3-Stage Max Flow Claryum
- Best value: Culligan EZ-Change
- Most reliable: Multipure Aquaversa MP750
Given the importance of drinking water, water filters are on the list of continuously tested products in the Good Housekeeping Home Improvement & Outdoor Lab. The Aquasana Claryum 3-Stage Max Flow has been our top pick for three years running for its ability to remove a slew of contaminants while improving the taste of your tap water. A few other under-sink water filters made our winners list for other reasons, like their low price or easy installation.
A note about certifications: All water filters sold legally in the U.S. must clearly indicate which standards set by NSF International they meet, following rigorous, third-party testing. Our experts use this information to determine the complete list of contaminants a filter will remove.
Best Deal
Pros
- Superb filtration, including PFAS
- Easy to install
- Won't clog prematurely or slow to a trickle
Cons
- Takes up more cabinet space than some
- Higher filter-replacement costs than some other models
BEST FOR: I recommend the Aquasana to anyone looking for top-level protection at a competitive price. It is certified to NSF standards 42, 53, and 401, which cover 78 contaminants, including lead, cysts, and microplastics. The filter even captures PFAS, also known as forever chemicals, because they don’t break down in the environment or in our bodies.
During operations testing, our experts noted that the Aquasana was very easy to install and that replacing the filters was simple thanks to the twist-off design. The dispenser delivered superb filtration without premature clogging or any drop in flow rate, even though one of our expert testers used it for several months at home for everything from cooking to filling the coffee machine each morning.
Our design experts liked that the dispenser comes in three finishes: brushed nickel, chrome, and oil-rubbed bronze.
TAKE NOTE: One of the few knocks against the Aquasana is that its 3-stage design takes up more cabinet space than filters that rely on a single filter. Also, because you do have to replace multiple filters, the operating cost with this system is relatively high. So if you’re short on cabinet space and have a tight budget, you might want to consider one of our other picks.
| Filter type | Pre-filter, activated carbon and catalytic carbon with ion exchange |
| Filter capacity | 800 gallons |
| Dimensions | 4.25" x 12" x 12.875" |
| Flow rate | 0.72 gpm |
| Filter cost per year | $140 |
Pros
- Excellent price
- Simple installation and filter replacement
- Takes up less space in the cabinet
Cons
- Doesn't remove pharmaceuticals, herbicides, and pesticides
BEST FOR: If money is a concern, the Culligan’s EZ-Change under-sink filter is far and away the best value from our tests. Besides its low initial cost, replacement filters are relatively affordable at around $70 per year.
Everything needed for installation comes with the device, including mounting hardware and a water supply adapter. Since the system uses only one filter, it takes up very little space in the cabinet, and it lived up to its EZ-Change name with its twist-on, twist-off filter mechanism. As for filter performance, the system is certified to capture a respectable range of contaminants, including lead, mercury, and cysts, and it reduces chlorine taste and odor.
TAKE NOTE: If you’re looking for maximum protection from contaminants, you won’t get it with this Culligan, since its granular-activated carbon filtration is not quite as robust as that of other top picks. For example, the filter is not certified to NSF standard 401, which covers pharmaceuticals, herbicides, and pesticides.
Also, its filter needs to be replaced every 500 gallons, which is below the 700 to 800 gallons we see with other systems, making the Culligan a better fit for small households.
Finally, the dispenser that comes with the EZ-Change looks like a budget buy, with its basic design and the fact that it only comes in a chrome finish, which might not coordinate with your kitchen faucet or other finishes in the room.
| Filter type | Granular activated carbon |
| Filter capacity | 400 gallons |
| Dimensions | 14.25" x 9.25" x 8.4" |
| Flow rate | 0.5 gpm |
| Filter cost per year | $80 |
Pros
- Space-efficient design
- Excellent filtration
- Resists clogging
Cons
- Dispenser is less sturdy than some other models
- Replacement filters are harder to come by
BEST FOR: This Multipure is the under-sink water filter I chose for my home when we renovated the kitchen nearly a decade ago. It costs more than other systems, but I'd go for it again because it's held up well over the years.
I also like that its housing is made of stainless steel rather than plastic. That feels more environmentally conscious, and metal is highly durable, as backed by Multipure’s lifetime warranty on the device. The housing is also quite compact, measuring just 8.5 inches by 5.75 inches, so it takes up minimal space under the sink (important since storage is at a premium in our city home).
Like the Aquasana, the Multipure meets NSF standards 42, 53, and 401, delivering high-level protection with no drop-off in flow rate. In my home, we dispense at least 2 gallons a day for the kids' water bottles for school and sports, as well as other hydration needs, and I only need to replace the filter once a year. One quibble: The countertop dispenser occasionally needs to be tightened by hand at its base, which we haven't seen with other tested filters, but, as I said, we handle it a lot.
TAKE NOTE: Price will be the biggest deal breaker. Even with all the benefits listed above, the Multipure costs $400 to $500 more than other systems our team recommends. Of course, if you end up going through a few cheaper water filters every decade, when a single Multipure would do the job, as it’s been doing in my case, the math changes.
Take the long view: If there’s a good chance you’ll be moving house in the next few years, it probably makes sense to choose a less expensive system. But if you’re in your forever home, I’d give the Multipure serious consideration.
| Filter type | Solid carbon block |
| Filter capacity | 750 gallons |
| Dimensions | 5.8" x 5.8" x 8.5" |
| Flow rate | 0.75 gpm |
| Filter cost per year | $96 |
Pros
- Easy installation and filter replacement
- Compatible with existing faucets
Cons
- Filters need to be replaced more frequently
BEST FOR: We recommend this water filter for renters because it's the only model from our latest tests that doesn't require a hole in your sink deck to install a side dispenser faucet. Instead, it hooks up directly to the cold-water line of your main kitchen faucet, filtering all the cold water that comes out.
Thanks to its streamlined, single-cartridge design, the setup of the Aquasana Claryum Direct Connect was straightforward, though at 20 inches tall, some testers said the filter had to be installed lying down in their cabinet, which took up more storage space.
Our experts verified that the filter is certified to NSF Standards 42, 53, and 401, meaning it effectively removes contaminants such as chlorine, lead, pharmaceuticals, and more. Testers found it handy for filling up coffee pots and other large containers.
TAKE NOTE: If your main reason for putting in a filtration system is to get pure drinking water, this might not be the best option for you. That's because you end up treating much more water than systems that use a side dispenser, meaning you'll need to replace filters more frequently, which adds to the total operating cost.
| Filter type | Solid carbon block |
| Filter capacity | 784 gallons |
| Dimensions | 3" x 20" |
| Flow rate | 1.5 gpm |
| Filter cost per year | $175 |
Pros
- Exceptional filtering
- Relatively compact, tankless design
- Smart controls
Cons
- Not suited to well water
- Needs to be plugged into an outlet
BEST FOR: For homeowners seeking the highest level of protection from contaminants, reverse osmosis (RO) filtration has always been our recommendation. But the systems used to come with huge caveats, starting with the fact that their equipment was big and bulky enough to fill a closet. They were also inefficient, wasting up to 5 gallons for every gallon filtered.
That’s changed in recent years, as evidenced by the Waterdrop X16. Though larger than other under-sink water filters we tested, it’s small enough to fit in a cabinet, which is a huge improvement over earlier-generation RO filters. And its waste-to-filtered-water ratio is down to 3:1.
Like other RO systems, the Waterdrop X16 works by pushing pressurized water through a semi-permeable membrane. It is NSF 58-certified, one of the highest standards, so it can withstand everything from heavy metals to pharmaceuticals to PFAS.
I also like the device’s intelligent design, including the filter light indicator on the faucet and the smart monitoring panel, which shows the amount of TDS (total dissolved solids) being filtered from your water.
TAKE NOTE: I recommend RO systems to homeowners who have confirmed, through a professional water test, that harmful contaminants are present. In other cases, these systems can be overkill, especially given their high upfront cost.
A couple of other things to note about the X16: the system needs to be plugged in, so you’ll need to add an electrical outlet if there isn’t one. And it is not intended for well water, as large particulates can cause clogging.
| Filter type | Reverse osmosis |
| Filter capacity | 400 gallons |
| Dimensions | 18.12" x 5.67" x 17.72" |
| Flow rate | 0.4 gpm |
| Filter cost per year | $130 |
How we test water filters
In the Good Housekeeping Institute Home Improvement & Outdoor Lab, our engineers and home improvement experts work together to evaluate under-sink water filters and identify top-performing options for your home. Over the last five years, we’ve evaluated more than 20 under-sink water filters through a combination of hands-on testing, home-use trials with consumer testers, and analysis of specifications and third-party certifications across the category.
Hands-on evaluations were conducted in the Home Improvement & Outdoor Lab by our engineers and product analysts, along with home-use trials where consumer testers installed and used the filters to assess real-world performance.
Our evaluations focus on the following criteria:
✔️ Installation: Testers assess how easy each filter is to set up. This includes rating the user manuals for clarity of instructions. We also check that all necessary parts for installation are included, such as mounting hardware and water line adaptors. And we evaluate how easy it is to replace the filters.
✔️ Filter performance: Our experts considered only water filters certified by NSF International, the organization that develops public health standards and certification programs for the industry. Because contaminant removal requires specialized lab equipment, we relied on NSF International certifications to evaluate what each filter is proven to remove (some standards cover only lead, like NSF 372, while others also include agricultural and industrial toxins, like NSF 401).
✔️ Reliability. We tracked flow rate during Lab testing and extended home use to identify any noticeable drop in water pressure before filter replacement. We also consider a brand’s track record based on prior Home Improvement & Outdoor Lab evaluations and long-term use by our experts.
What to look for when shopping for an under-sink water filter
Under-sink water filters are also known as point-of-use filters because they treat only water from a single source, typically the kitchen faucet. The basic mechanics are the same across models, but there are a couple of variables to consider.
✔️ Filtration: There are several different types of filters, depending on your needs. If you get your water from your city, you should receive an annual Consumer Confidence Report (CCR) telling you what contaminants were detected in your municipal water supply in the past year. It’s also a good idea to test your water regularly. These are two main types of filters:
- Activated carbon—in which a carbon-based filter acts like a magnet, absorbing contaminants from the water—is the most common technology. There are two types: solid-block, with a dense structure that is excellent at capturing impurities, and granular, which tend to be less expensive but aren’t as effective at filtering. Multi-stage filters, or two-stage filters, might also include a pre-filter to remove larger sediment, as well as a second carbon filter to improve odor and taste. Sometimes there is even a third filter, such as an additional carbon block or a UV sterilizer, to kill bacteria and viruses. The three-stage filters tend to cost more, so make sure it’s really necessary.
- Reverse osmosis (RO) is a newer type of filter that captures contaminants by pushing pressurized water through a semipermeable membrane. The process is extremely effective, but it's more expensive and less efficient—and many systems require a tank that won't fit under your sink. Before you invest in an RO water filter, our experts recommend testing your water to determine whether a conventional filter will provide enough protection.
✔️ Installation: While every system is unique, most come with a filter housing that gets mounted to an inside wall of your sink cabinet. Always check the dimensions listed in our product reviews (or on the manufacturer's website) to ensure there's room in your cabinet. One end of the filter ties into your cold-water line via a flexible connection. A second connection goes from the other end of the filter to the dispenser, which sits on your sink deck. Installing the dispenser is often the trickiest part, since it involves drilling a hole in the countertop. Capable DIYers should be able to handle the project, but it might be worth calling in a plumber if you’re less experienced, especially if your water line needs to be modified.
✔️ Maintenance: The main consideration is filter replacement and filter capacity. Take note of the steps and costs involved in the process. Our pros look for models with long-lasting filters and high filter capacity (400 gallons is good; 600+ gallons is better), affordable replacement filters ($100 or less per year), and simple “tool-free” filter swapping.
✔️ Flow rate: The flow rate refers to how much water can flow through a filter within a given amount of time. It's usually measured by gallons per minute (gpm). The higher the flow rate, the better your water pressure will be.
Why trust Good Housekeeping?
Dan DiClerico has been writing about the residential water filter market for 25 years, reviewing dozens of products and systems from all the leading brands. In his role as director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute, DiClerico oversees water filter testing alongside our health and technical experts.
We also consult with outside organizations, including experts from NSF International, the organization that develops public health standards and certification programs for the industry, and the Water Quality Association (WQA), a not-for-profit trade group representing the U.S. water treatment industry.
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