PFOS Detected in Water Well 14

On June 2, 2020, City of Paramount staff provided the City Council and Paramount residents with an update on the monitoring of per- and poly-flouroalkyl substances (PFAS) in Paramount’s water.

Water testing completed on February 3, 2020, and confirmed on February 19, 2020, March 22, 2020 and April 20, 2020, indicate levels of perflourooctanesulfonate (PFOS) — a substance in the PFAS family — that are above the State of California’s notification level (NL). Results detected PFOS in one of the City’s three municipal wells, Well 14, at an average level of 7.9 parts per trillion (ppt) — slightly above the NL of 6.5 ppt and well below the response level (RL) of 40 ppt.

wdt_ID Water Terms
1 The Notification Level (NL) means that the concentration level of a contaminant in drinking water delivered for human consumption does not pose a significant health risk but warrants notification.
2 The Response Level (RL), when exceeded, requires further action recommended by the State Water Resources Control Board to reduce public exposure to the compound, by either removal of the source water from service, or providing treatment of that water.
3 The unit part per trillion (ppt) equates to one drop of water in 20 olympic size swimming pools put together; one drop of water in 42 million gallons of water; or one drop of water in a lake.

See the below chart for a summary of the testing results for PFOS. (Testing results for perflouroctanoate (PFOA), the other PFAS chemical tested for, were non-detect.)

Although regulatory agencies do not require the City to do so, the City voluntarily shut down Well 14 on February 20, 2020, while awaiting the confirmation test results, and the well continues to be offline. The City has taken the opportunity to complete required preventive maintenance on the well. To continue to meet the demand for water, Wells 13, 15 and additional imported water are being used to supply water to residents.

“PFAS is a complex issue affecting cities across the state and the country, and I’m proud of our City’s efforts to voluntarily go above and beyond state requirements, conducting testing and being proactive to ensure the safety of our community’s water supply,” said Mayor Peggy Lemons. “Residents can be assured that we are continuing to provide residents with healthy, safe and reliable water.”

The drinking water notification levels and response levels for PFOA and PFOS were updated by the State Water Resources Control Board in August 2019. While Paramount’s previous testing results were non-detect and therefore below the notification levels, the City volunteered to run additional tests to determine whether or not PFOA or PFOS were in the water system.

PFAS are a large group of man-made substances that includes PFOS and PFOA. They are commonly found in consumer and industrial products, such as carpets, rugs, waterproof clothing, upholstery, food paper wrappings, non-stick products (e.g., cookware) fire-fighting foams, and metal products. High concentrations of PFAS are believed to cause adverse health effects, including developmental effects to fetuses during pregnancy or to breastfed infants, cancer, liver effects, immune effects, thyroid effects and high cholesterol. However, these chemicals are still unregulated, without a U.S. EPA Maximum Contaminant Level that would set a legal threshold for the amount safely allowed in drinking water.

The City of Paramount plans to conduct quarterly testing for PFOS for Well 14 moving forward, while exploring potential treatment systems.

Residents interested in viewing the City Council update can find the staff report online and view the City Council PowerPoint presentation here. For additional information, please visit

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