How to Choose a Water Filter Pitcher: NSF/ANSI 42, 53 and 401 Explained

Short answer: Choose a water filter pitcher by working backward from your water. Read your local water quality report, list the contaminants you want to reduce, then buy a pitcher that is certified for those exact contaminants and confirm the model on the certifier's public listing. NSF/ANSI 42 covers taste and odor issues such as chlorine, NSF/ANSI 53 covers health-related contaminants such as lead, and NSF/ANSI 401 covers up to 15 emerging compounds.^{Source [1]}

Pitchers are the cheapest and easiest filters to set up, but the boxes are crowded with numbers and claims. This guide explains what those numbers mean and gives you a simple process for picking one.

Step 1: Find out what is in your water

NSF's own advice is to begin with your local water quality report and then look for a filter that addresses what is in it.^{Source [3]} If you get water from a community water system, your utility publishes this report each year; EPA calls it a Consumer Confidence Report.^{Source [7]} Our guide on how to read your water quality report explains the tables.

Two situations call for more than the report:

• Lead. Lead often comes from plumbing inside or near the home, and EPA says testing is the only sure way to know whether there is lead in your water because you cannot see, taste or smell it.^{Source [5]}
• Private wells. The report covers public systems, not private wells. See how to choose a water test for options.

Step 2: Understand the three main pitcher standards

NSF/ANSI standards are the most common certifications for home filtration products.^{Source [1]} For pitchers, three matter most.

Source: NSF.^{Source [1]} NSF also says filters certified to NSF/ANSI 401 can help reduce microplastics.^{Source [3]}

Two points trip people up:

1. The numbers are not a ranking. 401 is not "better" than 53. They cover different contaminants.
2. A standard is a menu, not a guarantee. Each product is tested and certified for specific claims within a standard. The NSF page lists claims under each standard and notes that "claims vary by product."^{Source [1]} A pitcher certified to NSF/ANSI 53 for cyst reduction only does nothing you can count on for lead.

Step 3: Read the box the right way

NSF suggests checking three things on the packaging: whether it carries a mark from a certifying organization, whether it lists the specific contaminants that were verified, and whether any usage limits are noted.^{Source [2]}

Look for wording that names both a standard and a contaminant, for example "certified to NSF/ANSI 53 for lead reduction." Phrases such as "tested to" or "meets the requirements of" without a certifier's mark are not the same thing as certification.

Step 4: Check the performance data sheet

The performance data sheet is where the useful numbers live. NSF says it typically lists:^{Source [2]}

• the rated service cycle, in gallons or liters, after which the filter needs changing
• the rated service flow
• maintenance requirements, including how often to replace the cartridge
• the testing organization and the contaminants for which performance was validated
• any warranty

Use the rated service cycle to estimate real cost. Divide the cartridge price by its rated gallons, then compare that per-gallon cost across pitchers you are considering, using how much water your household drinks.

Step 5: Verify the exact model

Marks can be outdated or copied. NSF recommends checking the certification body's website to confirm a product is currently certified.^{Source [3]} For NSF, search the public listing of certified drinking water treatment units by brand or model, and confirm that the claims you care about appear for that model.^{Source [4]}

Make sure the listing matches both the pitcher and the replacement cartridge you will actually buy.

Choosing by goal

On PFAS, EPA adds a caveat: as of April 2024, the certification standards did not yet show that a filter removes PFAS down to EPA's new drinking water limits, though reducing PFAS still lowers exposure. EPA also notes filters work only when maintained on the manufacturer's replacement schedule.^{Source [6]}

For a printable side-by-side worksheet, use our water filter checklist.

Using a pitcher well

Certification only holds if you use the filter as tested:

• Change cartridges on schedule. EPA says using a cartridge after it has expired can make it less effective at removing lead.^{Source [5]}
• Use cold water only. EPA advises against running hot water through a filter and recommends cold water for drinking, cooking and baby formula. Boiling does not remove lead.^{Source [5]}
• Follow the setup instructions, including any pre-soak or flush steps for a new cartridge.
• Mind usage limits. NSF notes that activated carbon systems carry a warning not to use them with water that is microbiologically unsafe or of unknown quality without disinfection.^{Source [2]}

If lead is your main concern

Lead needs a few extra steps beyond buying the right pitcher, because it usually comes from pipes and fixtures and varies from tap to tap.

• Test first. EPA says testing is the only sure way to know whether there is lead in your water. Your state or local drinking water authority can point you to certified labs, and EPA puts testing costs at about $20 to $100.^{Source [5]}
• Ask your water supplier. It may know whether the service connector used in your home or area is made of lead. How long to run your tap depends on whether you have a lead service line and how long it is, so ask your utility for its recommendation.^{Source [5]}
• Flush stagnant water. The longer water sits in pipes, the more lead it may contain. Before drinking, EPA suggests flushing your pipes by running the tap, taking a shower, doing laundry or running a load of dishes.^{Source [5]} Then fill the pitcher.
• Pick a pitcher certified for lead reduction, not just one certified under NSF/ANSI 53 for another contaminant, and replace the cartridge on time.^{Source [1]Source [2]}

Keep your test result. If you change filters later, you can compare against it.

What a pitcher costs over a year

The sticker price of a pitcher is a small part of the cost. The ongoing cost is the replacement cartridges, and the performance data sheet tells you how many gallons each one is rated for.^{Source [2]} To compare two pitchers fairly:

1. Estimate how many gallons your household filters a week.
2. Divide each cartridge's rated service cycle by that number to get weeks per cartridge.
3. Work out cartridges per year, then multiply by the cartridge price.
4. Add the pitcher price to get a first-year total.

A cheaper pitcher with short-lived cartridges can cost more over a year than a pricier one. Our water filter checklist has space to record these numbers side by side.

When a pitcher is not enough

A pitcher may not suit you if your report or test shows a contaminant no pitcher is certified for, if you need large volumes for cooking, or if you want whole-home treatment. Faucet-mounted, under-sink and reverse osmosis systems are other point-of-use options; EPA's PFAS research looked at activated carbon, ion exchange and reverse osmosis point-of-use systems.^{Source [6]}

Frequently asked questions

Does NSF/ANSI 53 mean a pitcher removes lead?

Only if lead reduction is one of its listed claims. NSF/ANSI 53 covers more than 50 possible health-related claims, and each product is certified only for the ones it was tested for. Check the package or the NSF listing for the word lead.

Is NSF/ANSI 401 better than NSF/ANSI 53?

No. The numbers are not a ranking. 42 covers aesthetic issues, 53 covers specific health-related contaminants, and 401 covers up to 15 emerging compounds. A pitcher can carry one, two or all three, each for specific claims.

How often should I change a pitcher filter?

Follow the rated service cycle on the performance data sheet, usually given in gallons or liters, or the manufacturer's time limit if sooner. EPA notes that using a lead filter past its life can make it less effective.

Do pitcher filters remove PFAS?

Some are certified to reduce certain PFAS under NSF/ANSI 53. EPA advises checking the label and the NSF listing for the specific PFAS you want to reduce, and notes that certification standards as of April 2024 did not yet match its new drinking water limits.

Can I put hot water through a filter pitcher?

No. EPA advises against running hot water through a filter and recommends using only cold water for drinking, cooking and making baby formula.