How to Remove PFAS from Water

You can reduce PFAS in drinking water as it passes through a certified filter; total time depends on installation and any laboratory testing. The filter begins treating water during use, but selecting a device and verifying its performance take longer. For other concerns, see drinking water quality.

Where do PFAS in water come from?

PFAS are a large group of manufactured chemicals used in products and industrial processes. They can reach groundwater and surface water through releases from manufacturing facilities, firefighting foam, landfills and other contaminated sites. A water source can be affected even if PFAS were never used in your home.

EPA has set public drinking water limits of 4.0 parts per trillion (ppt) each for PFOA and PFOS, two individual PFAS. A water ph calculator can help with a separate water-quality question, but pH cannot tell you whether PFAS are present or whether a filter removes them.

These PFOA and PFOS limits apply to public water systems, not private wells, and do not cover every PFAS. If you use a public supply, your utility is a starting point for local information. If you use a private well, arranging a test is generally your responsibility.

How does the body handle PFAS?

The body eliminates some PFAS slowly. Treating drinking water reduces future exposure, but it does not rapidly clear PFAS already in the body, and drinking extra water is not a proven way to speed their removal.

How do you reduce PFAS in drinking water?

Activated carbon, reverse osmosis and ion exchange can reduce PFAS, but performance depends on the specific chemicals, the product, the water and maintenance. No technology name alone guarantees that a particular device will reduce every PFAS.

Method	How it works	What to check
Activated carbon	PFAS can attach to carbon in the filter.	Look for a specific certified PFAS reduction claim and replace the carbon as directed.
Reverse osmosis	Water passes through a membrane that can reduce PFAS.	Check the certified claim, installation needs and membrane replacement schedule. The system also produces reject water.
Ion exchange	Special resin can capture PFAS from water.	Confirm the resin and device have the relevant PFAS claim; an ordinary water softener should not be assumed to remove PFAS.

Identify your water source. Determine whether your drinking water comes from a public system or a private well. For a public supply, check the utility's water-quality information or ask for its PFAS results. For a well, contact a qualified laboratory or local health department about testing, especially if contamination is known nearby.
Review the PFAS results. Note which compounds were measured, their concentrations, the sampling date and the location. A result for PFOA or PFOS does not tell you the level of every other PFAS. If there are no current results for your source, arrange testing or ask the health department what information is available.
Choose a device with a specific PFAS reduction claim. Look for independent certification that identifies the PFAS the device was evaluated to reduce. Certification to a general water-filter standard alone is not the same as a verified PFAS reduction claim. Compare the certified claim with the compounds found in your water when possible.
Check the device's limits and fit. Read the certified performance information, rated capacity and manufacturer's instructions. A reduction claim does not guarantee that every PFAS will be removed or that the treated water will meet a particular limit under all conditions. Check that the device fits the intended faucet, dispenser or plumbing and that replacement parts are available.
Decide where treatment is needed. A point-of-use filter treats water at a particular tap or dispenser; it does not automatically treat every tap. Plan to use the treated water for drinking and for food or drinks made with water. If you are considering treatment for the whole house, ask a qualified installer about the equipment and maintenance it requires.
Install and prepare the device. Follow the manufacturer's installation, preparation and flushing instructions. Keep the instructions and record the installation date so you can identify the right replacement components later. If the unit requires professional installation, confirm who will service it.
Maintain the filter. Replace cartridges, membranes or other components on the manufacturer's schedule, and track when they are due. A filter can lose effectiveness as its media is used, even when water still flows and looks normal. Follow the instructions for disposing of used components.
Verify performance when appropriate. If PFAS are a known concern, ask a qualified laboratory about testing treated water and comparing it with an untreated sample. Collect samples as the laboratory directs, and keep the results with your maintenance records. If results remain concerning, contact the laboratory, health department or device manufacturer for help assessing the system.

Do not rely on boiling to remove PFAS. Boiling can reduce the amount of water while leaving PFAS behind, potentially increasing their concentration. Do not assume a PFAS filter also protects against unrelated contaminants or microbes unless its claims and instructions say so.

Can foods or binders remove PFAS?

No food, infused water or over-the-counter binder has been established as a way to remove PFAS from drinking water or reliably clear them from the body. Do not substitute a supplement for safer water or filtration; ask a clinician before taking a binder specifically for PFAS.

How should you test water for PFAS?

Start with existing information. Ask your public water utility for its PFAS results, or contact your local health department about testing a private well. Check the date, sampling location and list of compounds: an older result, or one taken elsewhere in a system, may not describe the water at your tap now.

For an independent test, use a laboratory qualified to analyze drinking water for PFAS. Ask which compounds it measures, its reporting limits and whether it can test both untreated and filtered water. If you want to compare PFOA or PFOS with the EPA limits, ask whether the laboratory can report concentrations low enough for that comparison.

Use the laboratory's supplied containers and follow its collection instructions; improper sampling can affect the result. If you test a filter, tell the laboratory where it is installed and ask how to collect the untreated and treated samples. A home pH reading cannot confirm PFAS removal.

Compare each result with the relevant limit for that specific compound, paying close attention to the units. A result reported as not detected means the laboratory did not find it above its reporting limit; it does not prove that the water contains none. Ask the laboratory or health department to explain results you do not understand.

When should you see a doctor or stop using the water?

Contact your local health department for guidance if testing identifies PFAS or officials report contamination in your supply. Ask about a suitable alternative, such as water from a source with documented PFAS testing, while you arrange treatment. Do not assume bottled water is PFAS-free without checking available information.

Discuss exposure concerns with a clinician, particularly if you are pregnant, preparing infant formula, caring for a child or have a medical condition that makes safe drinking water especially important. A clinician can help decide whether medical evaluation is appropriate; a blood test, if considered, does not identify the source of exposure or remove PFAS.

Stop relying on a filter for PFAS reduction if it is damaged, overdue for replacement or not working as directed; use a suitable alternative until the problem is corrected. If a health authority advises you not to drink the water, follow that advice, and seek prompt medical care for an urgent health concern rather than waiting for water-test results.