Occoquan Watershed Fish Consumption Advisory

This fish consumption advisory does not impact your drinking water.

April 14, 2026 - The Virginia Department of Health (VDH) has issued a fish consumption advisory for the Occoquan Watershed due to levels of Perfluorooctane Sulfonate (PFOS) found in fish. The advisory is located here.

This is not a drinking water advisory. Prince William Water’s treated drinking water remains safe, and no drinking water advisories are in effect. Prince William Water purchases much of its drinking water wholesale from Fairfax Water, which has information posted on its website at https://www.fairfaxwater.org/news/occoquan-reservoir-fish-advisory-not-related-drinking-water-safety.

The fish advisory for the Occoquan River, Occoquan Reservoir and tributaries is based on PFOS levels found in fish tissue—not in drinking water. PFOS can build up in fish over time through a process called bioaccumulation, meaning fish can accumulate much higher levels than those found in the water itself. 

Background

PFOS is part of the class of more than 6,000 manmade chemicals—per- and polyfluoroalkyl substances (PFAS)—used in the manufacture of a wide variety of industrial and household products designed to resist heat, water, oil and stains. They are often referred to as “forever chemicals.” 

Like our regional and national water utility colleagues, Prince William Water supports national efforts to limit exposure to these compounds, which enter the environment through industrial and household uses. Prince William Water also encourages restrictions on non-essential uses of PFAS compounds. 

In 2024, the Environmental Protection Agency (EPA) established new, stringent maximum contaminant levels (MCLs) for PFAS in drinking water, which will take effect in 2029. Some treated water samples from the Occoquan Reservoir have slightly exceeded the new PFOS MCL. Prince William Water is working with its wholesale providers to meet these new standards and protect public health.

If you have additional questions about drinking water quality, you can view our annual Water Quality Report or contact our Regulatory Affairs Office at water_quality@pwwater.org or 703-335-7976.