Most refrigerator filters are taste filters. That’s the honest description of what they do. They make water taste better by reducing chlorine. They don’t remove lead.
This matters if your home has older plumbing, old brass fixtures, or a lead service line. In those situations, trusting a refrigerator filter to protect you from lead is a mistake.
NSF 42: The Standard Most Fridge Filters Hold
NSF/ANSI 42 is the certification for aesthetic contaminants. Aesthetic means taste and appearance, not health. The standard covers chlorine taste and odor, particulates (cloudiness), and turbidity. It does not cover any contaminant listed on EPA’s health-based primary drinking water regulations.
A filter certified only to NSF 42 has been tested to reduce what makes water taste bad. Nothing about it addresses health-based contaminants. Lead, PFAS, arsenic, bacteria, VOCs, nitrates, none of these are covered under NSF 42.
Most name-brand OEM refrigerator filters carry NSF 42. That covers the purpose most people actually use them for: improving the taste of their tap water.
NSF 53: The Standard Required for Lead Removal
NSF/ANSI 53 covers health-effect contaminants. Lead is the most commonly cited. A filter certified to NSF 53 for lead has been tested under controlled conditions to reduce lead concentration by at least the certified rate, typically 97-99% in independent testing.
The certification is specific. A filter with NSF 53 for lead may not have NSF 53 for other contaminants under that standard (which also covers cysts, certain VOCs, and other health-based concerns). The listing on nsf.org specifies exactly which contaminants each model is certified for.
Some refrigerator filters hold both NSF 42 and NSF 53. These exist and are the right choice for households with lead concerns. Common examples include the LG LT1000P, certain Samsung filter models (verify the specific model number, because the same brand’s other models may not have NSF 53), and Whirlpool EveryDrop filters EDR1RXD1 and EDR3RXD1. The list changes as manufacturers update certifications. Always verify at nsf.org rather than relying on packaging.
How to Check Your Specific Filter
The model number is printed on the filter itself, usually on a label or molded into the plastic.
Take that model number and go to nsf.org/certified/dwtu. Search for the exact model. The result shows every certification that specific model holds and the specific contaminants covered under each certification.
Marketing language on the box doesn’t substitute for this check. Filters described as “advanced filtration,” “premium,” “elite,” or “maximum protection” don’t necessarily hold NSF 53. NSF certification is the only meaningful verification.
The PFAS Gap
No standard OEM refrigerator filter removes PFAS. No manufacturer has built an under-sink refrigerator filter that holds NSF P473 certification for PFAS reduction.
This isn’t a knock on any specific brand. It’s a technical challenge. PFAS removal at the levels now regulated by the EPA requires either reverse osmosis or specialized media that doesn’t fit the cartridge form factor of OEM refrigerator filters.
If PFAS is a concern in your water, you need a separate solution: an NSF P473-certified pitcher (Clearly Filtered is the most widely available option with this certification), or an NSF 58-certified under-sink or countertop RO system. The RO system can supply a dedicated drinking tap alongside the refrigerator or can be plumbed to the refrigerator’s water line, depending on your setup.
The Expired Filter Problem
A carbon filter that’s past its rated life and hasn’t been replaced can release previously captured contaminants back into the water. Activated carbon works by adsorbing contaminants onto its surface. When the surface sites are fully occupied (the filter is exhausted), it can no longer hold contaminants and may release some of what it captured.
Most refrigerators display a filter replacement reminder. Manufacturers typically rate refrigerator filters at 6 months or 200-300 gallons. For a family that uses the refrigerator dispenser as their primary drinking source, 6 months is a reasonable cycle.
Don’t run the filter well past its rated life and assume it’s still working. An exhausted filter isn’t neutral, it’s potentially worse than unfiltered water for some contaminants.
The Concrete Check
Look up your refrigerator filter’s model number. Go to nsf.org/certified/dwtu. If your filter only shows NSF 42, you have a taste filter.
If you have pre-1986 plumbing, old brass faucets, or a home built before 1986 (when the EPA banned lead solder and pipe in residential construction), or if you live in a city with documented lead service line issues, NSF 42 alone is not enough. Find out if your refrigerator model accepts an NSF 53-certified cartridge. If not, add a separate point-of-use filter on your drinking tap.
See NSF certification standards explained for a full breakdown of what each certification covers, and the lead contaminant page for information on lead sources in household plumbing.