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Water Quality
Providing customers with safe, reliable, and affordable drinking water, now and in the future.
Outstanding Performer Award 2025
Gresham received an Oregon Health Authority award for excellence in treating, storing and delivering drinking water. We are committed to providing safe, high-quality water to the community.
- Water Quality Report
- Drinking Water Sources
- Groundwater Safety
- Each year the City of Gresham provides the Drinking Water Quality Report to all of its customers.
- The report contains important information about Gresham’s drinking water and water system.
- The 2025 Drinking Water Quality Report contains results from the 2024 calendar year.
- Request a paper copy or translation of the report by calling 503-618-2525.
Gresham’s drinking water comes from three sources.
Bull Run Watershed
Located in a protected area of the Mt. Hood National Forest, managed by the Portland Water Bureau. Learn more about Bull Run.
Visit the Portland Water Bureau to learn more about Portland's water testing and water quality report.
Columbia South Shore Well Field
Columbia South Shore, managed by Portland Water Bureau, is used on occasion to supplement the Bull Run. Groundwater from these wells comes from three different aquifers:
- Blue Lake Aquifer
- Troutdale Sandstone Aquifer
- Sand and Gravel Aquifer
Cascade Well Field
Cascade, managed by Rockwood PUD and the City, taps into the Sand and Gravel Aquifer. Currently, this groundwater is used to supplement our supply from the Portland Water Bureau.
In 2020, the City and Rockwood Water People’s Utility District formed the Cascade Groundwater Alliance to expand Gresham’s groundwater system together. Cascade ground water will be the primary water source for Gresham in spring 2026. Learn more about the Cascade Groundwater Alliance.
Keep our groundwater safe
Join the City in protecting groundwater, our secondary source of drinking water. Groundwater is runoff from rain or other precipitation that soaks into soil, filling cracks in beds or rock deep underground, called aquifers.
The deep aquifers that are the primary sources of water supply have natural geologic protection from pollutants present at the land surface. Portland, Gresham, and Fairview work together to protect the well field.
How you can help
- Take care when storing or disposing household chemicals. Never pour them down a storm drain.
- Know if your older home has an underground heating oil tank. Check underground storage tanks for leaks.
- Report chemical spills and illegal dumping.
- Businesses have specific requirements for storing and using chemicals and is managed by the Groundwater Protection Program.