All water providers share the same goal: providing safe, reliable drinking water to the communities they serve. To do this, most water systems must treat their water. The types of treatment vary depending on the size of the system, whether they use ground water or surface water, and the quality of the source.

Water suppliers use a variety of processes to remove contaminants from drinking water. These individual processes can be arranged in a series of steps to make water safe.

The Willamette Water Supply System Treatment Plant will be a state-of-the-art system designed to meet current and future drinking water regulations.


Step-by-step process used to make safe water:

  • Step 1:
    Intake: Raw Willamette River water flows through intake screens and is pumped to the start of the process.
  • Step 2:
    Enhanced Coagulation, Sedimentation: Raw water is treated with a coagulant and enters the Actiflo process, which quickly removes turbidity and other contaminants.
  • Step 3:
    Ozonation: Serves multiple functions including disinfection (to kill bacteria, viruses, Giardia, Cryptosporidium); breakdown of organic chemicals; breakdown of taste/odor causing compounds; and enhanced removal of organic material by the filters. After bubbling through the water, the ozone quickly decomposes into harmless oxygen gas.
  • Step 4:
    Granulated activated carbon filtration (GAC): Disinfected water passes through GAC filters which effectively remove turbidity and dissolved organic molecules.
  • Step 5:
    Sand filtration: Removes any remaining silt or particles.
  • Step 6:
    UV Disinfection: Destroys illness-causing pathogens.
  • Step 7:
    Chlorination: Filtered water is treated with chlorine which protects the water as it travels through the distribution system to city reservoirs.




The Safe Drinking Water Act is a federal law that ensures the quality of Americans' drinking water. The law sets national health-based standards for drinking water and requires many actions to protect drinking water and its sources.