On average, around 95% of our drinking water comes from the Green River. We filter it at the source and deliver it to your taps through hundreds of miles of water mains. The Green River replenishes itself regularly from snow and rainfall, giving us an ample supply of clean drinking water.
We also maintain a backup resource of groundwater wells from an aquifer that runs through central and south Tacoma. In a normal weather year, the wells supply about 5-10% of our drinking water, mostly in the drier summer months. The wells are regularly tested, and water from the wells is treated before it is distributed to customers. We maintain standards that meet or exceed regulatory requirements, ensuring our drinking water is safe for our customers.
Federal and state authorities set the standards for drinking water. By the end of 2022, the Environmental Protection Agency plans to update the federal requirements for per and poly-fluoroalkyl substances (PFAS), types of chemicals commonly associated with firefighting foam and a wide variety of stain-resistant, water-resistant, and non-stick consumer products. We are closely monitoring the regulatory process and will meet the new regulations once they become known.
In 2018, we tested all our water sources for PFAS. To date, PFAS have not been detected in the water we use from the Green River watershed that provides roughly 95% of our drinking water. In our well system, we took two of our 24 wells out of service based on those results. The PFAS levels in the remaining groundwater wells are below current state requirements. We plan to test all sources again in 2023.
Most of our wells are located within the South Tacoma Groundwater Protection District where all development and business activity is permitted and regulated by the City of Tacoma, protecting the quality of our groundwater.
While our modeling anticipates that our groundwater use will increase over the next few decades, the Green River will continue to be our primary water source. Our projections also indicate we will have ample supply to meet our customers’ needs.
Click here to see our staff’s recent update to the Public Utility Board
Learn more about our water sources here:
Click here to read our most recent water quality report
Click here for information about PFAS from Washington State’s Department of Health