Does a Brita filter remove PFAS?

Not reliably. Standard activated carbon pitcher filters reduce some PFAS but not consistently and not completely. Unless the filter carries NSF P473 certification for PFOA and PFOS reduction, you can't rely on it for PFAS. Most Brita pitchers are NSF 42 certified (taste and odor) only.

What percentage of PFAS does RO remove?

NSF 58-certified RO systems remove 90–99% of PFOA and PFOS in testing. Real-world performance varies with membrane age, water pressure, and temperature. A membrane approaching the end of its useful life will show declining rejection rates.

Do refrigerator filters remove PFAS?

Generally no. Most refrigerator filters use activated carbon and are certified to NSF 42 or 53 — not for PFAS. Some newer models have upgraded filters. Check the filter's NSF certifications specifically; don't rely on the appliance brand's claims.

How often should I replace an RO membrane for PFAS removal?

Most manufacturers recommend 2–5 years for the RO membrane itself. Pre-filters (sediment and carbon) every 6–12 months. Post-filter (polishing carbon) every 12 months. Check your system's output TDS periodically — a rising TDS reading in filtered water indicates declining membrane performance.

How to Remove PFAS from Drinking Water

RO removes PFAS. Carbon alone doesn’t.

That’s the short answer. Here’s the data behind it and what to actually do.

What the NSF Testing Shows

NSF/ANSI 58 is the certification standard for reverse osmosis drinking water systems. Systems tested and certified under NSF 58 have demonstrated removal of a defined set of contaminants, including PFAS.

NSF P473 is a product-specific certification that tests for PFOA and PFOS reduction. A filter or system carrying NSF P473 has been verified to remove those two specific compounds.

For activated carbon filters: NSF 42 covers taste and odor (chlorine reduction). NSF 53 covers health-related contaminants including some VOCs and lead. Neither NSF 42 nor NSF 53 requires PFAS testing.

The research on activated carbon for PFAS shows inconsistent results. Granular activated carbon (GAC) used in some under-sink filters reduces PFAS, but the reduction rate varies widely depending on the carbon source, contact time, and which PFAS compounds are present. Longer-chain PFAS (PFOA, PFOS) are better adsorbed than shorter-chain compounds.

Bottom line: If you need reliable PFAS reduction, look for NSF 58 or NSF P473 certification on the specific filter or system you’re buying.

Step-by-Step: Choosing a PFAS Removal System

Step 1: Confirm PFAS Is Present

A mail-in lab test using EPA Method 533 or 537.1 tells you which PFAS compounds are present and at what concentrations. This matters because:

Different PFAS compounds have different removal rates across filter types
You may have compounds beyond PFOA and PFOS that aren’t covered by NSF P473
Knowing the concentration helps you track treatment effectiveness over time

Best Mail-In Water Tests covers certified labs that offer PFAS panels.

Step 2: Choose Your Treatment Type

Under-sink RO system (recommended for most households)

An under-sink RO installs below your kitchen sink and produces filtered water on demand to a dedicated faucet. It treats drinking and cooking water without affecting the rest of your home’s water supply.

Capacity: typically 50–100 gallons per day. More than enough for a household’s drinking and cooking needs.

Key certifications to look for: NSF 58 (required), NSF P473 (additional PFAS confirmation).

Cost: $150–$400 for the unit, plus periodic filter replacement ($50–$100/year).

Whole-house RO system

Treats all water entering the home. Practical if you’re also concerned about PFAS in shower water or have a commercial need. Much more expensive ($3,000–$10,000 installed) and requires professional installation.

Most households don’t need whole-house RO for PFAS. The primary exposure pathway is drinking and cooking water.

Countertop RO

If you rent and can’t install under-sink, countertop RO units connect to your faucet and don’t require drilling. Performance is comparable to under-sink but flow rate may be slower.

Step 3: Verify the Certification

Before buying, look up the specific model number on the NSF product search database (nsf.org) to confirm certification. Manufacturer marketing claims on packaging don’t always match actual certifications. The NSF database shows exactly what was tested and what the system is certified for.

Step 4: Install and Establish a Filter Replacement Schedule

For under-sink RO:

Sediment pre-filter: every 6–12 months
Carbon pre-filter: every 6–12 months
RO membrane: every 2–5 years
Post-filter (polishing carbon): every 12 months

A TDS (total dissolved solids) meter is a cheap way to monitor membrane performance. Test your filtered water quarterly. If TDS climbs from near zero toward 50+ mg/L, the membrane is losing effectiveness.

Step 5: Test After Installation

Run the system for 2–3 weeks before retesting (to flush the new membrane). Then submit a sample to the same certified lab you used before installation. The before/after comparison confirms actual removal rates in your specific water conditions.

What Won’t Work

Boiling — concentrates PFAS, doesn’t remove them.

Standard pitcher filters — not reliably effective unless NSF P473 certified.

Refrigerator filters — same issue.

Softeners — don’t remove PFAS at all. Different technology entirely.

Basic faucet filters — NSF 42 carbon filters won’t cut it.

Product Recommendations

See the full comparison: Best Under-Sink RO Systems