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Home filters and filtration systems

A reverse osmosis (RO) water filtration system

Home filters and filtration systems

PFAS can be released to the environment by manufacture and use of items that have PFAS in them. PFAS in the environment may enter surface water, groundwater, and drinking water wells. Some drinking water wells may have PFAS in amounts that are high enough to cause concern for human health. For these residents, in-home water filtration systems are recommended to lower the levels of the PFAS in their drinking water.

In May 2016, the U.S. Environmental Protection Agency (USEPA) set a lifetime health advisory (LHA) level for two PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in drinking water. These are the chemicals that were used in the certification for filters at that time.

Because of various state’s efforts to regulate PFAS at lower levels, and to include additional compounds in regulation, as of 2022 filters are certified to reduce combined levels of PFOA, PFOS, PFHxS, PFNA, PFHpA, PFBS, and PFDA in water to below 20 parts per trillion (ppt). Currently filters are not certified to reduce other PFAS.  

Certified filters and filtration systems

Filters can be certified for total PFAS reduction. When buying a filter, read the packaging to be sure it has proper certification to reduce PFAS, such as the following certifications from the NSF International/American National Standards Institute (NSF/ANSI):

  • NSF/ANSI 53 certification for total PFAS reduction.
    • Look for this certification on filters like those made with granulated activated carbon (GAC).
  • NSF/ANSI 58 certification for total PFAS reduction.
    • Look for this certification on reverse osmosis filtration systems.

These certifications mean the filter has been tested using a standardized process and is successful at reducing specific PFAS in drinking water.

Types of filtration systems

Both granular activated carbon (GAC) and reverse osmosis (RO) filters can reduce PFAS substances. Both systems provide less water flow than a standard water faucet.

  • Granular activated carbon (GAC)

    • reduces the amounts of PFAS and some other contaminants in drinking water.
    • has a carbon filtration cartridge which captures the contaminants.
    • provides more water flow than an reverse osmosis (RO) system.
    • has cartridges that are rated to treat more gallons of water than those in an reverse osmosis (RO) system and are less expensive to replace.
    • are often easier to install than reverse osmosis (RO) systems.
    • does not remove minerals from water.

  • Reverse osmosis (RO)

    • reduces the levels of more contaminants in water (including arsenic and nitrates) than a granular activated carbon (GAC) system.
    • typically consists of a sediment filter, carbon filters, and a reverse osmosis (RO) system membrane. Reverse osmosis (RO) systems force water through the membrane under pressure, leaving the contaminants at the membrane.
    • provides less water flow than a granular activated carbon (GAC) system.
    • uses approximately three times as much water as it treats, and discharges the untreated water to the sewer or septic system.
    • removes minerals from water. Some systems include remineralizers.
    • requires more frequent changes of the filtration cartridge and the reverse osmosis (RO) membrane.
    • is more costly.

Owning a filter or filtration system

The following information applies regardless of which type of filter or filtration system you own.

  • Maintenance

    Water filters require maintenance for them to be effective.

    This maintenance often includes having to change your filter cartridge and/or membrane regularly.

    Follow the manufacturer’s instructions for installing, operating and maintaining your filter.

  • Disposal

    The filter cartridges may be disposed of in household trash.

    Drinking water filter cartridges are not considered hazardous waste.

  • Results

    If you have been notified that PFAS were found in your drinking water well sample, alternate water or a filtration system may be available to you.

    For more information, contact your local health department.  

  • Funding

    There is not money available to help pay for a filter for PFAS.

    If you live in an area that is under investigation for PFAS contamination, you may qualify for a free water filter.

    Call MDHHS at 800-648-6942 to learn more.

Frequently asked questions

  • What are the different types of filtration systems or filters available to me?

  • Where can I get an approved filter, and does it cost anything?

  • How long do the filtration cartridges last and how do I get a replacement?

Non-certified filtration systems

There may be other filters that lower PFAS. However, without the NSF/ANSI Standard 53 or 58 certification, it can be difficult to know which filters effectively reduce PFAS and which do not.

In 2007, the Minnesota Department of Health hired Water Science & Marketing, LLC and the Water Quality Association to determine if water filtration systems could lower PFAS in water. At that time, there was no NSF standard for reducing PFAS.

  • Fourteen filters were tested, and eleven of these were shown to sufficiently reduce the amount of PFAS in water.
  • Four of these filters were activated carbon devices and seven were reverse osmosis devices.
  • None of the devices were, or are currently, certified for PFAS removal.

It is important to note that the Minnesota Department of Health does not certify water filters. Summary of the Minnesota filtration study final report.

Need help understanding your drinking water test results?

You can call the MDHHS Environmental Health Hotline at 800-648-6942 to review your water test results with a toxicologist. 

The answer can be more complex than comparing the amount in your water to a drinking water amount intended to protect everyone. MDHHS can help you understand any potential risks and advise on next steps based on your results. 

MDHHS uses Public Health Drinking Water Screening Levels for PFAS to help people making personal choices about their drinking water sources.