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Portland Water Bureau

From forest to faucet, we deliver the best drinking water in the world.


1120 SW Fifth Ave, Suite 600, Portland, OR 97204

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Water Quality Trivia

By Lindsay Wochnick

The temperature of water in our distribution system fluctuates seasonally. What impacts can we expect to see with a mild winter and spring followed by early summer temperatures in the 90’s?

A.   Customers may notice warmer water from their cold water faucets.

B.   Shifts in algae populations may occur in the open reservoirs, which could affect the taste/odor of our drinking water.

C.   Minimal impacts will be seen as underground water mains act as a refrigerator.  Water temperature fluctuates only by a few degrees throughout the year.

D.   As water temperature increases, chlorine disinfectant levels can decrease.

Answer: A, B, and D can all occur with seasonal temperature fluctuations. 

This year, these impacts are seen sooner due to the mild winter and spring and 90 degree temperatures in June.  The Portland Water Bureau monitors algae in the system to ensure that no harmful species are present. Additionally, chlorine levels are adjusted seasonally to maintain adequate disinfectant levels to protect public health.

Questions or Concerns About Water Quality?
Contact the Water Bureau’s Water Line at 503-823-7525.


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