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Water Quality

  • Providing customers with safe, reliable, and affordable drinking water, now and in the future.  

    Water safety at home, public buildings 

    Flushing your water lines may reduce the risk of mold or bacteria in your system, if the water is not turned on regularly. Learn more from the Regional Water Providers Consortium.

    • Water Quality Report
    • Drinking Water Sources
    • Bull Run Update
    • Groundwater safety
    Water Quality Report

    Water Quality Report 2023

    • 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 2023 Drinking Water Quality Report contains results from the 2022 calendar year.
    • A paper copy or translation of the report can be requested by calling 503-618-2525.
    Drinking Water Sources

    Gresham’s drinking water comes from three sources:

    • The Bull Run Watershed, located in a protected area of the Mt. Hood National Forest, managed by the Portland Water Bureau.

    • The Columbia South Shore Well Field, also managed by the 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
    • The Cascade Well Field, 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. The new water system is under construction and will be complete in 2026. Learn more about the Cascade Groundwater Alliance 
      Bull Run Update

      Water quality update

      • Gresham’s primary source of water is the Bull Run watershed, a federally protected water source managed by the City of Portland. Gresham has two additional water supplies if needed.
      • Recent Bull Run water monitoring results detected small levels of Cryptosporidium. At this time, there is no evidence of an increased health risk.
      • The City of Gresham will continue to monitor water quality reports in coordination with Portland and local health agencies. 

      Precautions customers can take 

      • People with severely weakened immune systems should seek specific advice from their health care providers about drinking water.
      • You can use a filter. Make sure that it is labeled and certified to remove Cryptosporidium and is NSF/ANSI 53 or 58 rated. Look for the language “cyst reduction” or “cyst removal.” Reverse osmosis and carbon filters are the most common types of filters available. Make sure that the manufacturer states “absolute” pore size of 1 micron or smaller.


      Groundwater safety

      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. If we’re not careful, small amounts of chemicals – either spilled, leaked or dumped – can find their way into our aquifers.  

      How you can help


    1. Gresham receives drinking water from the Bull Run watershed. The City of Portland monitors and tests Bull Run water at the source. During heavy rains, testing may show positive results for cryptosporidium. Ongoing monitoring has not resulted in any drinking water advisories for Gresham or the greater Portland area.