Whole-house vs under-sink vs pitcher filters

Pitchers, countertop units, faucet filters and under-sink systems treat the water at one tap, and in our product list they are the only types with lead or PFAS claims certified in IAPMO's listing. Whole-house filters treat every tap, but none of the 15 whole-house units in our product list has a contaminant-reduction listing at IAPMO, and several of the certifications they cite cover only the tank or its materials.

What each type does

• Pitchers and refrigerator filters often use activated carbon. CDC says their main purpose is to improve taste and smell rather than safety (CDC), though some pitchers are certified for lead (table below).
• Point-of-use filters (faucet-mounted and under-sink) deliver filtered water to a single tap (CDC). Portland's water bureau calls them a good choice for contaminants that come from your home's plumbing, such as lead (Portland Water Bureau).
• Whole-house (point-of-entry) filters treat water as it comes into the home, so every tap gets filtered (CDC). They do not fix problems in the plumbing after the filter, and one that removes chlorine also removes the disinfectant, which can lead to bacterial growth and corrosion in home plumbing (Portland Water Bureau).

What each can be certified for

Certification is per model and per claim. These are the standards you will see, with their titles as IAPMO's certificates print them:

For lead, EPA says to look for certification to NSF/ANSI 53 with a lead-reduction claim, plus NSF/ANSI 42 for particulate reduction (Class I); its consumer tool covers point-of-use and pitcher filters (EPA). For PFAS, EPA says to look for NSF/ANSI 53 or 58 (EPA). Standards 61 and 372 cover the components, not what the filter removes: Aquasana's Rhino data sheet describes its NSF/ANSI/CAN 61 certification as "for Materials Safety Requirements Only" (data sheet).

What IAPMO's listings show

"Certified" here means Certified (IAPMO listing, checked 16 Oct 2026). NSF and WQA listings were not checked automatically (methodology), so some products may also be listed there. Three examples:

• Pitcher: IAPMO lists the PUR PPF951K under NSF/ANSI 53 for lead and total PFAS, at a capacity of 40 gallons (IAPMO).
• Under-sink: the Aquasana AQ-MF-1 is listed under NSF/ANSI 53 for lead and PFOA/PFOS, at 784 gallons (IAPMO).
• Reverse osmosis: the Waterdrop G3P600 is listed under NSF/ANSI 58 for lead and TDS (IAPMO) and under NSF/ANSI 53 for PFOA/PFOS (IAPMO).

The whole-house units

• Aquasana Rhino WH-1000: the data sheet says the tank is certified by WQA for materials safety and structural integrity, and "Not certified for contaminant reductions by WQA" (data sheet). Its chlorine claim: Brand claim, no certification cited.
• Waterdrop WHF21-PG: IAPMO lists it only under NSF/ANSI/CAN 372, the lead-content standard for components (IAPMO).
• Aquasana HealthShield WH-HS: the data sheet says WQA certified it to NSF/ANSI 53 and 401 (data sheet). Brand says certified, not found in IAPMO's listing; check NSF, and WQA's listings, since WQA is the body it names.
• A. O. Smith AO-WH-FILTER: the brand says NSF certified it to NSF/ANSI 42 for chlorine taste and odor (A. O. Smith). Brand says certified, not found in IAPMO's listing; check NSF in NSF's listings.

The Waterdrop's chlorine claim and the UV stage of the Rhino Well are also Brand says certified, not found in IAPMO's listing; check NSF. The other 10 whole-house units do not tie a certification to what they say they remove: Brand claim, no certification cited.

Matching the type to the problem

• Lead from pipes or fixtures: a point-of-use or pitcher filter certified to NSF/ANSI 53 for lead, at the tap you drink from (EPA). See lead pipes and lead filters.
• PFOA or PFOS in your utility's results: a filter certified to NSF/ANSI 53 or 58 for them (EPA). See PFOA and PFOS limits explained.
• Chlorine taste or smell at every tap: whole-house carbon units claim this; check whether a certificate backs the claim, as above.

Capacity differs by type too: 40 gallons for the PUR pitcher filter, 784 for the AQ-MF-1 cartridge and 1,000,000 for the Rhino tank (data sheet). See filter replacement schedules.