PFAS Information for Private Well Owners

Learn more about PFAS impacts for private well owners.

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Are you concerned about PFAS in your well?

Are you concerned about PFAS in your well? We’re here to help - Contact us at 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 information.

 

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 man-human-made (synthetic) chemicals designed to resist heat, water and oil. PFAS are known as “forever chemicals” because they do not easily break down and degrade naturally in the environment. PFAS were developed and utilized due their water-, grease-, and stain-resistant properties and by the 1950s and 1960s, were widely used in industrial and consumer products such as fire-fighting foams, stain- and water-resistant clothing, carpets, cleaning products, non-stick cookware and food packaging. 

PFAS have been found in air, soil and water around the world, and are persistent in the environment. Although certain PFAS are no longer manufactured in the U.S., these chemicals are still produced internationally and imported into the U.S. in consumer goods. 

PFAS Sources

PFAS enters the environment at sites where they are made, used, disposed of, or spilled, making groundwater susceptible to PFAS contamination. PFAS are mobile and can be mobilized by rainwater runoff and transport into streams and lakes, which may eventually migrate through soil and enter into groundwater aquifers that are used as sources for drinking water.

For more information on PFAS and Zone 7’s PFAS management strategy, click here 

PFAS impact to the Livermore Valley Groundwater Basin

Zone 7 began sampling for PFAS within the basin in 2019 and has since identified a PFAS footprint in both the upper and lower aquifers centered primarily within the Main Basin. Zone 7 continues to monitor PFAS within the groundwater at over 150 monitoring sites within the Basin annually.

Based on the known and hydrogeology of the basin, domestic wells that are located outside of the groundwater basin are believed to be at less risk than wells within the groundwater basin. If your well is located within the Livermore valley groundwater basin, you 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.

Should i be concerned about pfas?

There are over 15,000 different PFAS compounds, but only a handful have been identified as posing significant risk. According to the Agency for Toxic Substances and Disease Registry (ATSDR), studies have suggested chronic exposure to PFOA and PFOS may be linked to increased cholesterol levels, increased risk of high blood pressure or pre-eclampsia in pregnant women changes in liver enzymes, decreased vaccine response, and small decreases in infant birth weights.

Additionally, the EPA has classified PFOA and PFOS as having potential carcinogenic effects in humans. The U.S Environmental Protection Agency (EPA) and the U.S Centers for Disease Control and Prevention Agency for Toxic Substances and Disease Registry (ATSDR) continue to investigate the human health impacts of chronic exposure to PFAS.

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. Domestic wells are not considered public water systems, and as such, residents with private domestic wells are not legally required to treat for or ensure that their water meets the public water supply enforceable limits or treat it. The MCLs established by the EPA may be used as a reference for private well owners to evaluate their own health risks

It is important to note that consuming water containing 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) 

Researchers are working to better understand how toxic or harmful PFAS are to people and the environment. If your water has been found to have PFAS and you have specific health concerns, you may wish to consult with your doctor. 

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:

What do the pfas test results mean?

What information is in my lab test result?

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: 

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 no approved regulations for levels of PFAS in private domestic wells. For reference, you may want to compare the results in your well to the Environmental Protection Agency’s (EPA) maximum contaminant Levels (MCLs). The list of MCLs are below: 

list of MCLs

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.

What should i do if my well contains pfas?

 If test results indicate that your well may contain elevated levels of PFAS, you may want to consider a water treatment or filtration system that is certified to reduce levels of PFAS. Ultimately, the decision to filter 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) 

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.
   

  • Granular Activated Carbon (GAC): 
Granular activated carbon (GAC) filtration is a widely-available and effective technology for removing PFAS. Contaminated water is passed through a pressure vessel or filter box containing granular activated carbon (GAC). PFAS is absorbed by the activated carbon and sticks to the carbon’s porous surface. GAC effectiveness at removing PFAS can vary based on typed of carbon used in the filter.​
  • Reverse Osmosis:
Reverse osmosis is extremely effective at removing PFAS. Water is forced through a semi-permeable membrane that captures PFAS and other contaminants. This processes splits water into two streams – clean water (also known as permeate), and a contaminated stream (known as reject, concentrate, or brine) that is sent to a drain or discharged.
  • Ion Exchange:
Ion exchange is an effective technology to filter water with elevated PFAS concentration. Water is passed through a vessel containing anion exchange media (often tiny resin beads), which act as a powerful magnet to attract and hold contaminated materials within the water (e.g. PFAS).

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:

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, follow the filter manufacturers’ recommendations for filter treatment system maintenance.

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. Therefore, it is important to evaluate your health and risk based on potential pathways into the body. Zone 7 recommends filtering water that may be directly or indirectly consumed by humans or animals. 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)

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.

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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:

ATSDR: https://www.atsdr.cdc.gov/pfas/index.html

EPA PFAS General Info: https://www.epa.gov/pfas/pfas-explained

EPA Treatment Options: https://www.epa.gov/system/files/documents/2024-04/pfas-npdwr_fact-sheet_treatment_4.8.24.pdf 

California State Water Resources Control Board (Water Board) PFAS General Info: https://www.waterboards.ca.gov/pfas/