How CR Tests Water Filters
We test water filter pitchers by timing how long it takes the pitcher to finish filtering 1 quart of water at multiple intervals until we’ve gone through as much as 40 gallons of water, which is the typical lifespan of this type of water filter. We also measure whether a filter’s flow rate slows down (gets clogged) over the course of the cartridge’s capacity and, if so, by how much.
If a manufacturer claims that a pitcher meets NSF/ANSI standards for removing specific contaminants, such as chlorine and lead, we verify each claim. NSF International and the American National Standards Institute develop filtration standards.
We also check claims of flavor and odor reduction by spiking water with commonly found compounds that can make water smell and taste like a sewage treatment plant, damp soil, metal, or a swimming pool. A trained panel of professional tasters evaluates how successful the filters are at removing these flavors and odors.
The best performing filters work well enough that most people wouldn’t be able to discern a palatable difference between the filtered water and pure spring water. But on the other end of the spectrum, if it does a poor job, you’ll probably be able to taste the difference.
We test under-sink filters by measuring how effectively they remove flavor and odor taints from a CR-created "control water" sample. Then we examine how close that control water compares with regular filtered water. We determine the flow rate by the time it takes to filter 1 quart of water, and clogging reflects whether and how the filter’s flow rate slowed over the course of a cartridge’s lifespan. We also verify under-sink filter claims of lead and chlorine removal.
What's in Your Water?
The Environmental Protection Agency requires community water suppliers to provide a Consumer Confidence Report to customers every July. A CCR states the levels of contaminants detected in the water and how they compare with the EPA’s drinking water standards. If you rent an apartment, contact your building manager or local water company for a copy.
Community water systems providing water to 100,000 or more people must post the reports online. If you’re on well water, you won’t have a CCR because the EPA doesn’t regulate private wells. In that case, check with the Centers for Disease Control and Prevention for information on well testing and treatment.
The water quality report tells you about the water in your municipality, but if your home was built before lead-free pipes were mandated in 1986, a test is the best way to assess the quality of the water coming out of your faucets at home. There’s no safe level of lead exposure, according to the EPA.
In the CR-Guardian study, almost every test sample had measurable levels of PFAS, which are linked to cancer, learning delays in children, and thyroid disease. More than 35 percent exceeded the maximum safety threshold specified by CR scientists and other health experts.
PFAS, found in hundreds of household products, are a growing concern. At least 2,858 communities in all 50 states and two territories have drinking water contaminated with PFAS, according to a June 2022 analysis by the Environmental Working Group, an advocacy organization. Thus far, the EPA hasn’t set an enforceable legal limit for PFAS in drinking water—however, there is now a roadmap stretching into 2024 that will hopefully move PFAS regulation in the right direction.
Your state or local health department might offer free water test kits, and test kits are sold at home improvement stores, where they generally cost $10 to $30, depending on what exactly they test for. The EPA recommends sending samples to a certified lab for analysis. Your local water authority can offer a list of labs. Or you can check the EPA’s list or call the agency’s Safe Drinking Water Hotline at 800-426-4791. For more on testing your water, see our interactive guide.
Fit the Filter to Your Needs
What a filter removes from water varies. Our water pitcher tests found that all models effectively remove chlorine and four models remove lead. All under-sink filters in CR’s ratings meet the strict standard of lead and chlorine removal.
Once you know what’s in your tap water, choose a filter that best suits your needs. Look at the filter’s packaging for its contaminant removal certifications, if any. Third-party labs that certify products to NSF standards include the CSA Group, Underwriters Laboratories (UL), and the Water Quality Group (WQA), so you may see those certification seals, too.
All filters must be replaced periodically to function effectively. Check the specs in the full view of our ratings to compare the costs of replacing filters for one year. For example, the pitcher filters we test range from $16 to $150; you’ll also see which models have a filter-life indicator, a handy feature that tells you when it’s time to change the filter.
Filtering Your Choices
Water filter pitchers are one of the most widely used choices, but there are other filtration systems available for the home. Factor in your budget, your water consumption, maintenance, and, most important, the contaminants found in your water before purchasing a new filter.
Water Filter Pitcher
Water pitchers are great if you’re on a budget, don’t have space to install a permanent filter, or are renting. However, you do need to keep filling them over and over, where other types filter constantly. The best water pitcher model we test does a stellar job of removing chlorine without sacrificing cartridge life or flow rate. Some others are slow, prone to clogging, or have a short filter life. A small pitcher stored in the refrigerator might suffice for one or two people, but a large size may be more convenient for a family that consumes several gallons of water a day.
Price of tested filters: $16 to $150.
Faucet-Mounted Water Filter
If you’re looking for easy installation, these are a good choice for filtering drinking and cooking water. Simply unscrew the aerator from the threaded tip of the faucet and screw on the filter. Faucet-mounted filters let you switch between filtered and unfiltered water. On the downside, they slow down water flow and don’t fit on all faucets, including those with a pullout sprayer.
Price of tested filters: $32 to $85.
Countertop Water Filter
These filters are also easy to install: Just remove the faucet aerator, then screw the filter onto the faucet. Because they attach to the faucet end, you don’t need to spend time under your sink, working on plumbing. This also makes them handy for renters, who might not have a landlord’s okay to perform more significant modifications. CR’s tests found that countertop filters are less likely to clog than pitcher filters or faucet-mounted filters. But they can clutter a countertop, and they don’t fit all faucets.
Price of tested filters: $101 to $217.
Under-Sink Water Filter
Under-sink filters are arguably the most convenient option, once you get past the more difficult installation. They don’t clutter the counter (but do take up space under the sink), and they look better than the alternatives. Like countertop filters, these can filter lots of water. Instead of cluttering the counter, they rob space from the cabinet beneath the sink. They may also require professional plumbing modifications and drilling a hole through the sink or countertop for the dispenser.
Price of tested filters: $75 to $157.
Reverse Osmosis Water Filter
If you’re facing more serious water contamination issues, you may need the more powerful filtration of a reverse osmosis system. Using standard household water pressure, water is forced through a semipermeable membrane, then through filters. Reverse osmosis filters can remove a wide range of contaminants, including dissolved solids. They can be extremely slow, rob cabinet space, and typically create 3 to 5 gallons of wastewater for every gallon filtered. You must sanitize them with bleach periodically, and the membrane and filters must be replaced, per manufacturer’s recommendation.
Price of tested filters: $85 to $150.
Refrigerator Water Filter
Water-and-ice dispensers are common on bottom-freezer and side-by-side refrigerators. The water line typically runs through a built-in filter. Most filters can be easily replaced by simply pushing and twisting. A replacement filter costs about $50 or more, and you’ll need to change it every six months or so. Third-party water filters are widely available at a lower cost but may be less reliable or effective. Depending on the particular filter, fridge filters can reduce many of the same contaminants as a countertop or under-sink filter.
Consumer Reports is not currently testing refrigerator water filters.
