Notice to Drinking Water Customers PFAS Detection Drinking water samples collected from: City of Kennewick Water System, ID#38100, Benton County, Ranney Collector #5 (S04 & S05 - blended) have exceeded the Running Annual Average (RAA) for the following per- and polyfluoroalkyl substances (PFAS) above the drinking water standard, the State Action Level (SAL). PFAS Contaminant RAA Level (ppt*) SAL (ppt) PFOS - perfluorooctane sulfonic acid 10.5 4.0 PFHxS - perfluorohexane sulfonic acid 16.0 10 *ppt = parts per trillion In 2021, the Washington State Board of Health (Board) adopted a rule that requires our water system to test for a new class of contaminants not yet regulated by the Environmental Protection Agency (EPA), which included health-based standards called state action levels (SALs). On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation for PFAS. Starting April 2029, the new EPA standards, called maximum contaminant levels (MCLs) will become effective. In January 2026, the Board aligned the SALs with the MCLs so there is one consistent drinking water standard. We are required to notify you when our results exceed the health-based standard. What should you do? There is nothing required of you at this time. The Washington State Department of Health (DOH) recommends the following. • If you are pregnant, breastfeeding, or mixing infant formula with tap water, use an alternative drinking water source. You can also install water treatment in your home, using Point of Use Water Treatment 331-699 (PDF) such as reverse osmosis or an activated carbon filter, that is certified to lower the levels of PFAS in your water. There are several different types of filters you can purchase depending on your budget and water flow rate PFAS Point-Of-Use Filter Options 331-713 )PDF). Follow the manufacturer’s maintenance and replacement recommendations. • You can learn about PFAS and the steps you can take to reduce your exposure to PFAS in drinking water, while your water system considers options. Visit the PFAS information webpage on the DOH website to learn more. • Do NOT boil your water to reduce PFAS. Boiling your water will not reduce PFAS levels. • If you have specific health concerns, consult your healthcare provider. What do we know about PFAS? PFAS are a large family of chemicals that are tasteless, colorless, and odorless. They do not occur in nature and are manufactured to make many products including stain-resistant carpets and fabrics, nonstick pans, fast food wrappers, grease-proof food containers, waterproof clothing, makeup, and a special kind of firefighting foam. Over many years, these unregulated chemicals were released into the environment from factories, fire training areas, everyday products, and other places. Once released, PFAS do not break down easily and last a long time in the environment. Some PFAS seeped from surface soil into groundwater. Public health officials are concerned about PFAS in drinking water because of new information about their potential human health effects. When ingested, some PFAS can build up in the body and, over time, may increase to a level where health effects could occur. Human health effects of PFAS are still being actively researched and health advice continues to evolve. What are the potential health effects? There are many different PFAS. We are still learning about their health effects in people. • PFOS. Some people who drink water containing PFOS in excess of the SAL over many years may have increased health risks such as cardiovascular, immune, and liver effects, as well as increased incidence of certain types of cancers including kidney and testicular cancer. In addition, there may be increased risks of developmental and immune effects for people who drink water containing PFOS in excess of the MCL following repeated exposure during pregnancy and/or childhood. . • PFHxS. Some people who drink water containing PFHxS in excess of the SAL over many years may have increased health risks such as immune, thyroid, and liver effects. In addition there may be increased risks of developmental effects for people who drink water containing PFHxS in excess of the MCL following repeated exposure during pregnancy and/or childhood. What is Being Done The City is actively working on designing a treatment system for effective PFAS removal. The new treatment process is anticipated to be online and operational no later than April 2029 (however, City staff are planning for earlier). Current PFAS trends: https://www.go2kennewick.com/DocumentCenter/View/15575/Ranney-Collector-5-PFAS-Sample- Results?bidId= For more information, please call the City of Kennewick at (509) 585-4419 or email PWinfo@ci.kennewick.wa.us. Please share this notice with others who may drink this water, especially those who may not have received this notice directly (for example, people in apartments and businesses). We encourage you to post it in a public place, share copies by hand, or mail. The City of Kennewick Water System sent this notice to you on 7/12/2026.