Refrigerator Water Filters: What They Actually Remove, Counterfeits, and When to Replace

What a refrigerator water filter removes depends entirely on what it is certified for, and fridge filters vary widely. Many are certified only to NSF/ANSI 42, for chlorine taste and odor and sometimes particulates. Some also carry NSF/ANSI 53 health claims such as lead, cysts, certain pesticides and VOCs, and a smaller number list PFOA and PFOS. Some add NSF/ANSI 401 claims for “emerging” contaminants like certain pharmaceuticals. CDC says most fridge filters are not designed to remove germs. To know what yours does, look up its exact cartridge number in the certifier’s listing, buy genuine replacements, and change it on schedule.

How fridge filters work

CDC notes that pitcher filters and filters built into refrigerators often use activated carbon, mainly to improve taste and smell. Carbon traps chlorine and many organic chemicals on its surface. With the right design and certification, carbon filters can also reduce lead and some other contaminants.

What the certifications mean on a fridge filter

Standard	What it covers	Typical fridge filter claims
NSF/ANSI 42	Aesthetic effects	Chlorine, taste and odor, particulates
NSF/ANSI 53	Health effects	Lead, cysts, mercury, asbestos, certain pesticides and VOCs; some models list PFOA/PFOS
NSF/ANSI 401	Emerging contaminants	Certain pharmaceuticals (such as ibuprofen), BPA, estrone, some pesticides; some list microplastics

Two points make this table useful.

Certification is claim by claim. A filter certified to NSF/ANSI 53 for cysts is not certified for lead unless lead is listed. NSF says to look for NSF/ANSI 53 or 58 with lead listed among the contaminants reduced if lead is your concern. EPA’s consumer guide for lead filters says the same.

A “42 only” filter is a taste filter. When we reviewed NSF’s public listing of certified refrigerator filters in October 2026, a large share of models carried only NSF/ANSI 42 claims, typically chlorine reduction and taste and odor reduction. A smaller group carried NSF/ANSI 53 claims, and some of those listed PFOA and PFOS. We did not see a “Total PFAS” claim on fridge filters in that review. Listings change, so check the current entry for your model.

For a fuller explanation of each standard, see our NSF certifications guide.

How to find out what your filter removes

Find the cartridge model number on the filter itself or in your refrigerator manual.
Look it up in the NSF certified drinking water treatment units listing. You can search by brand, model or product type, including refrigerator filters. Listings show the replacement element number, the rated capacity in gallons and each certified claim. Other accredited certifiers, such as IAPMO and WQA, have their own directories.
Match numbers exactly. Certification applies to specific cartridges. An “equivalent” or “compatible” cartridge has its own certification, or none.
Read the performance data sheet, which lists each claim and the rated capacity.

If a box shows a certification mark but you can’t find the model in the certifier’s listing, treat the claim as unverified.

Counterfeit filters are a real problem

Refrigerator filters are a frequent target for counterfeiters. Fake filters often copy brand names and certification marks, as federal seizures show.

What enforcement has found: - In 2019, U.S. Customs and Border Protection (CBP) announced it had seized 5,202 counterfeit refrigerator water filters at the Los Angeles/Long Beach seaport. They copied Brita, GE, Frigidaire and PUR trademarks and carried counterfeit NSF certification markings. NSF had never tested or certified them. - In 2023, CBP announced a seizure of 3,940 refrigerator water filters at the same port, bearing NSF certification marks that had not been authorized. CBP noted it is “extremely difficult” for online shoppers to spot filters with fraudulent copied certifications.

What testing found: In 2018, the Association of Home Appliance Manufacturers (AHAM), an industry trade group, reported results from three independent labs that tested counterfeit fridge filters. AHAM said only 2 of 18 counterfeits kept reducing lead for a typical six-month filter life, 7 of 8 failed to remove 90 percent of cysts, and some leached compounds into water that had sat in them, including arsenic in some cases. These results come from an industry group with an interest in the issue and are not a peer-reviewed study, but they line up with the enforcement findings.

How to lower your risk: - Buy from the refrigerator maker or an authorized retailer. On marketplace sites, check who actually sells and ships the item. - Be wary of prices far below the genuine part. Unusually cheap replacements are a common warning sign. - Verify the cartridge in the certifier’s listing, not just by the logo on the box. Anyone can print a logo. - Watch for poor fit. A counterfeit may not seat properly and could leak.

When to replace a fridge filter

A filter used past its rated capacity is no longer performing to its certification. CDC says you need to maintain any filter to keep it working and prevent germs from growing in it, and to replace cartridges on the manufacturer’s schedule.

Gallons: In NSF’s refrigerator filter listings, rated capacities are commonly in the 200 to 300 gallon range. Your model’s listing or data sheet gives the exact figure.
Time: Manufacturers also set a time limit, and AHAM’s testing treated six months as a typical fridge filter life. Follow your manufacturer’s instructions and change at whichever limit you hit first.
Signs: slower flow from the dispenser, or chlorine taste and odor coming back.
After installing: follow the manufacturer’s instructions for flushing a new filter before drinking from it.

When changing a filter, CDC advises wearing gloves and washing your hands afterward. People with weakened immune systems should have someone else do it.

What a fridge filter won’t do

Remove germs. CDC says most pitcher and fridge filters are not designed to remove germs. During a boil water advisory, don’t rely on your fridge filter. Follow your utility’s instructions.
Fix hard water. Fridge filters don’t remove hardness. See our hard water guide.
Reduce nitrate, arsenic or fluoride. Carbon handles these poorly. Reverse osmosis is the usual home option. See reverse osmosis vs. carbon filters.
Protect against lead unless certified for lead. If you have lead service lines or old plumbing, confirm the lead claim in the listing, or use a separate filter certified for lead. Our lead guide covers other steps.

Do you need a better filter than your fridge’s?

It depends on your water. If your utility meets standards and you mostly want better taste, a genuine fridge filter certified to NSF/ANSI 42 and changed on time does that job. If you have a specific concern, such as lead from older plumbing or PFAS in your utility’s water, check whether your cartridge is certified for that exact contaminant. If it isn’t, consider a certified pitcher or under-sink filter. To see what’s in your water, look up your water system or read your water quality report.

Bottom line

A refrigerator filter is only as good as its certified claims and its replacement schedule. Look up your exact cartridge in the certifier’s listing, buy replacements from the manufacturer or an authorized seller, and change the filter by its gallon or time limit. Don’t assume a fridge filter handles lead, PFAS or germs unless the listing says so.