How to Filter Tap Water? | Match The Filter To Your Water

Filtering tap water starts with a water test, then matching a certified filter to the specific contaminant you need to remove.

Filtering tap water isn’t a one-size-fits-all job. The right approach depends entirely on what’s actually in your water. A basic pitcher filter that removes chlorine won’t help if you’re dealing with lead or PFAS. The smartest first move is checking your local water quality report or running a simple test, then choosing a filter certified for the specific contaminant you found.

Filter Types And What Each One Removes

Point-of-use filters treat water at a single tap or fixture, and they come in several forms. Each type targets different contaminants, so matching the filter to your needs matters more than picking the most expensive option.

• Pitcher filters use activated carbon to improve taste and odor, typically reducing chlorine and some particulates.
• Faucet-mounted filters attach directly to the tap and often combine carbon block with nonwoven material to catch sediment.
• Under-sink systems filter a dedicated faucet and can handle a wider range of contaminants.
• Reverse osmosis units push water through a membrane, removing a broader range of impurities including heavy metals.
• Whole-house systems treat water at the main line, covering every tap but not necessarily targeting the same contaminants as point-of-use filters.

A whole-house system and a pitcher filter aren’t interchangeable. The EPA notes that point-of-use filters make sense when you need treatment at one fixture, while whole-house units serve the entire plumbing system. Following the manufacturer’s instructions for installation and replacement is essential for the filter to work as intended.

The Certification Standard You Need To Check

Not all filter claims are equal. Look for the NSF mark on the packaging along with the exact standard number that matches your contaminant. Both the EPA and NSF stress this step — a filter certified for one contaminant isn’t automatically certified for another.

The standards you’ll see most often:

• NSF/ANSI 42 covers aesthetic issues like chlorine and taste or odor.
• NSF/ANSI 53 covers contaminants with health effects, including lead and PFAS.
• NSF/ANSI 58 applies to reverse osmosis systems.
• NSF/ANSI 401 covers emerging contaminants like pharmaceuticals.

For PFAS specifically, the EPA says to look for certification under NSF/ANSI 53 or 58 and to verify the specific PFAS claim on the product or the NSF listing. Checking the certification listing independently is the only way to confirm the filter actually does what the box claims.

Installing And Replacing Filters Properly

After installing or replacing any filter, discard the first three containers of filtered water before drinking. This flushes out loose carbon dust and primes the filter for use. Skipping this step means drinking black-tinted water that tastes like charcoal.

Follow the manufacturer’s replacement schedule rather than guessing. A filter past its rated capacity stops reducing contaminants and may even become a breeding ground for bacteria. If you’re comparing models, our tested roundup of top water filters breaks down which units handle which contaminants best.

An important caveat: some microbiological filters are designed only for public water supplies that are already safe, meant for temporary contamination events like a boil-water advisory. Read the use limitations carefully before assuming any filter protects against microbes. The EPA notes that boiling water for a full minute remains the most reliable emergency method for killing Cryptosporidium — filtration isn’t a universal substitute.

FAQs

Is “EPA approved” a valid filter certification?

No. The EPA regulates public water systems, not consumer filter performance. That phrase on a package is meaningless as a certification. Instead, check for the NSF mark and the specific standard number that matches the contaminant you want to remove, then verify the claim on the NSF listing itself.

Do pitcher filters remove lead and PFAS?

Only if the specific model is certified for those contaminants. Many pitcher filters handle chlorine and taste issues under NSF/ANSI 42 but aren’t certified for lead or PFAS. Check the packaging for NSF/ANSI 53 certification (or 58 for reverse osmosis) and confirm the specific contaminant claim on the certification listing.

When should I boil my water instead of filtering?

During a boil-water advisory or when you suspect microbial contamination, boiling for a full minute is the most reliable method, especially for Cryptosporidium. Filtration products for microbes have specific limitations and are typically intended only for supplies that are already microbiologically safe during intermittent contamination events.