PFAS Information for Private Well Owners
Learn more about PFAS impacts for private well owners.
Are you concerned about PFAS in your well?
Are you concerned about PFAS in your well and have questions? We’re here to help – contact us as groundwater@zone7water.com
This page contains information on PFAS for private well owners. Use the map below to find out whether your well may have PFAS in it. The FAQ below has additional for additional information.
Zone 7 actively monitors wells for PFAS within the Livermore Groundwater Basin. Use the map below to search for your address to see results of PFAS in nearby wells.
Disclaimer: This map is a tool to be used for informational purposes and may not reflect what PFAS levels may be in individual wells at any given time. If you are concerned with PFAS, Zone 7 recommends sampling your and sending the sample to a qualified analytical laboratory certified to analyze for PFAS.
What are PFAS and how does PFAS get into your well?
PFAS (Per- and Polyfluoroalkyl Substances) are a large group of synthetic chemicals designed to resist heat, water and oil. PFAS are used in a wide range of industrial and consumer products such as fire-fighting foams, stain- and water-resistant clothing, carpets, cleaning products, non-stick cookware and food packaging.
Since PFAS are used in array of industrial and consumer products, there could be many sources of contamination in water supplies. Common sources of PFAS include industrial facilities where PFAS are manufactured or used, wastewater, landfills and areas where fire-fighting foam was used. There are areas across the nation where PFAS have seeped into groundwater, lakes and rivers. These chemicals travel easily through the ground and may make their way into groundwater basins that supply drinking water.
For additional information on PFAS, please refer to the links below:
Should i be concerned about pfas?
PFAS have been found in air, soil and water around the world, and are persistent in the environment. People may be exposed to PFAS in many ways including drinking water contaminated by PFAS, eating foods that may contain PFAS (including fish), or even breathing air containing PFAS. They can accumulate in the human body over time and are toxic at relatively low concentrations.
For additional information please refer to the links below:
PFAS impact to the Livermore Valley Groundwater Basin
Zone 7 began sampling for PFAS withing the basin in 2019 and has since identified PFAS in both the upper and lower aquifers centered primarily within the Main Basin region within the Livermore Valley Groundwater Basin (Basin). Zone 7 continues to monitor PFAS within the Basin at over 150 monitoring sites within the Basin annually.
Zone 7 is not responsible for identifying potential sources but is managing PFAS under its PFAS management strategy.
In 2025, the San Francisco Bay Regional Water Quality Control Board identified two potential sources within the Basin in which it is investigating.
Based on the known hydrogeology of the Basin, domestic wells that are located outside of the Main Basin are believed to be at less risk than wells within the Main groundwater basin. If your well is located within the Main Basin, it may have a higher likelihood of containing elevated levels of PFAS. The only way to know if your well has PFAS is to test it.
Refer to the map at the top of this page which shows the location of the Livermore Valley Groundwater Basin. You may enter your address or click on the map to find nearby wells and sample results.
What Regulations Apply to Me as a Private Well Owner?
PFAS in private wells is not currently regulated, therefore there are no defined regulatory limits. Residents with private domestic wells are not legally required to treat for or ensure that their water meets the public water supply enforceable limits described below. Additionally, Zone 7 is not required to ensure that water in private domestic wells meets the public water supply enforceable limits.
On April 10, 2024, the U.S. Environmental Protection Agency (EPA) announced final maximum contaminant levels (MCLs) for six PFAS substances which require public water systems to monitor and meet these MCLs for public water supply wells.
Public Water Systems include Zone 7, Cal Water, Dublin San Ramon Service District (DSRSD), City of Livermore, and City of Pleasanton.
While domestic wells are not required to test for or meet these limits, the MCLs established by the EPA may be used as a reference for private well owners to evaluate their own health risks.
For more information on PFAS regulations, see Zone 7’s PFAS Information Page: https://www.zone7waterca.gov/post/pfas-information
How can I test my well for pfas?
As a well owner the only way to be 100% sure if your well water contains PFAS is by sampling and analyzing for PFAS. The map provided at the top of this page displays levels of PFAS in nearby wells. If you are concerned or believe your well may be at risk of containing PFAS, Zone 7 recommends testing your well water.
Zone 7 does not provide sampling or testing services. Residents are encouraged to contact a certified lab to analyze PFAS in your well water. A list of qualified labs may be found in the following links:
- https://www.waterboards.ca.gov/pfas/docs/pfas-laboratories.pdf
- https://www.epa.gov/system/files/documents/2022-01/ucmr5-approved-lab-list.pdf
What do the pfas test results mean?
Should you have specific questions regarding the test results or lab report, contact the laboratory who performed the analysis.
If you have concerns about PFAS levels detected in your water affecting your health, consider discussing them with your doctor.
If you sample and test your well water for PFAS, you will likely get a laboratory report back from the lab. Laboratory data reports will often contain more information than most people need to know, making them seem difficult to read and interpret. Each laboratory may present the information in differing ways. The easiest place within a laboratory report to start is to look for a section titled “Sample Results” (or similar).
Reports generally will have a line item for each PFAS analyte (specific PFAS compound) and several columns to report the sample result, and other information. PFAS are typically reported in ng/L (nanograms/Liter) but may also be reported in ppt (parts per trillion). Perhaps the most important information in the lab report are the Analyte and the Result. Below is an example of various components of a lab report and what it means.
Example Laboratory Reporting Table:
How to Interpret my results?
Now that you understand the lab report, how do you know if the result is “too high”? There are currently no regulations for levels of PFAS in private domestic wells. For reference, you may want to reference the results in your well to the Environmental Protection Agency’s (EPA) maximum contaminant Levels (MCLs), which are only enforceable for Public Water Systems. The list of MCLs are below:
Note: The MCLs are only enforceable to public water supplies, therefore as a private well owner, you are not bound by or required to filter your water if PFAS levels in your well exceed these limits.
If you are concerned about exposure to PFAS in your well affecting your health, you should consult your doctor.
What should i do if my well contains pfas?
If test results indicate that your well may contain elevated levels of PFAS and you are concerned, you may want to consider a water treatment or filtration system that is certified to reduce levels of PFAS. Ultimately, the decision to filter or treat your water is up to you.
It is important to note that consuming water with PFAS levels above the federal standard does not necessarily mean that adverse health effects will occur. The degree of risk from PFAS exposure depends on many factors including:
- Level of the chemicals
- How much a person is exposed and how long they’re exposed over time
- Individual factors (like genetics and lifestyle)
If your water has been found to contain PFAS and you have specific health concerns, you may wish to consult with your doctor. Zone 7 does not endorse or recommend any specific home treatment or filtration systems.
How can I treat my well water from PFAS?
There are several different treatment systems that have shown to reduce levels of PFAS in drinking water. These methods include Granular Activated Carbon, or GAC, Reverse Osmosis, and Ion Exchange. Each system filters or treats water in different ways and some may be more effective at treating specific contaminants or specific PFAS chemicals.
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Granular Activated Carbon (GAC):
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Reverse Osmosis:
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Ion Exchange:
Zone 7 recommends using the National Sanitation Foundation (NSF) as a resource to find the most appropriate equipment for in-home water treatment systems. NSF has multiple standards, NSF/ANSI 53 and 58 standards are the most appropriate water treatment systems for PFAS. NSF/ANSI standard 53 addresses health-related contaminants in drinking water systems.
As with all treatment and water filtration systems, proper maintenance, which may include regular filter or membrane replacement, is essential to ensure the system remains effective at removing PFAS.
Please review the links below for more information and resources on filters and treatment systems:
- EPA’s information on Reducing PFAS in Drinking Water with Treatment Technology
- EPA’s Reducing PFAS in your Drinking Water with a Home Filter Fact Sheet
- NSF Treatment systems for contaminants
- NSF certified filters & systems
Zone 7 does not endorse or recommend any specific home treatment or filtration systems.
how do i have a treatment system installed?
Always follow manufacture instructions for installation. For treatment systems that are designed to filter and treat your well water source for the entire home, Zone 7 recommends using a licensed well driller, water conditioner installer, or plumber with experience installing domestic water treatment systems. To ensure the treatment system continues to filter your water effectively, always follow the filter manufacturers’ recommendations for filter treatment system maintenance.
Zone 7 does not endorse or recommend any specific home treatment or filtration systems.
is it safe to use water with Pfas for non-drinking purposes? (e.g. bathing, washing clothes, pools/hot tubs, irrigating plants)?
Scientific evidence suggests that epidermal (skin) contact poses a lesser risk to human health than direct consumption by swallowing [1]. Therefore, it is important to evaluate your health and risk based on potential pathways into the body. Below are some water uses that may pose an increased risk if water is contaminated with PFAS:
- Consuming (drinking) water
- Water used for cooking
- Water used to grow foods that may be consumed (vegetables, fruit, etc.)
- Pools/ Hot Tubs (accidental swallowing, or open wounds)
If you are concerned about exposure to PFAS affecting your health, you should consult your doctor.
For more information on PFAS exposure, visit the links below:
Help Zone 7 monitor for PFAS:
Zone 7 continues to monitor wells across the basin, however we are unable to monitor every well within Zone 7’s service area. Help shape our understanding of PFAS by submitting your lab results to our PFAS database. Note: Your personal information will not be shared.
Where can i find additional information?
More information on the human health effects and routes of exposure to these compounds and other PFAS compounds can be found through the following links: