PFAS Monitoring
Silver Lake Water & Sewer District’s drinking water remains safe and protected from contaminants, including the group of manmade chemicals labeled per- and polyfluoroalkyl (PFAS) substances.
The District sources its water from the City of Everett. Due to the protected nature of their watershed, which prohibits activities like firefighting training, manufacturing, and agriculture, there are no point sources of PFAS within our source water.
What are Perfluoroalkyl substances (PFAS)?
PFAS are a group of chemicals that are used widely and are commonly found in things like firefighting foam agents, the manufacture of non-stick materials for cooking (such as Teflon), and fabric protectants.
Learn More:
Environmental Protection Agency
Washington State Dep't. of Health
Background and History of PFAS Monitoring
In 2016, The Environmental Protection Agency (EPA) released a health advisory for drinking water pertaining to two of the compounds found in the PFAS group: Perfluorooctanoic acid (PFOA) and Perflourooctanesulfonic acid (PFOS).
Health advisory levels are non-enforceable guidelines that are intended to protect human health. The health advisory level is 0.07 parts per billion (ppb) for PFOA and PFOS combined.
The Washington State Board of Health (WSBOH) recently revised the Group A drinking water rules to require water systems to monitor for select PFAS compounds beginning in 2023. WSBOH established state action levels (SALs) for five selected PFAS compounds as follows:
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Perfluorooctanoic acid (PFOA) - 0.010 ppb
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Perfluorooctane sulfonic acid (PFOS) - 0.015 ppb
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Perfluorononanoic acid (PFNA) - 0.009 ppb
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Perfluorohexane sulfonic acid (PFHxS) - 0.065 ppb
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Perfluorobutane sulfonic acid (PFBS) - 0.345 ppb
Exceeding a confirmed SAL requires a water system to provide public notification and follow-up monitoring. While exceeding a SAL does not require a water system to treat for the contaminant, the SALs are intended to advise water systems on when to take action to lower contaminant levels to provide for safe, long-term consumption of drinking water.
Testing Your Drinking Water for PFAS
In 2015, Silver Lake Water & Sewer District participated in monitoring for PFAS in its drinking water under the Unregulated Contaminant Monitoring Rule 3 (UCMR 3).
No PFAS compounds were detected in the Districts drinking water as shown in Table 1 below:
Table 1:
In 2023 through May 2024, the District monitored our drinking water quarterly for an expanded list of PFAS compounds under the EPA’s current Unregulated Contaminant Monitoring Rule (UCMR 5). Once again, no PFAS compounds were detected in the District's drinking water as shown in Table 2 below:
Table 2:
