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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 Regulations and Portland's Drinking Water

Portland's primary water supply is surface water from the Bull Run Watershed. Restricted access to the watershed and a watershed protection program have allowed Portland to meet stringent requirements for remaining an unfiltered water system.

Groundwater has been available as a back-up supply since 1986. The system is used to meet peak water demand during hot summer months. It is also used as an emergency source of supply when the Bull Run is not available. During the February 1996 flood, groundwater was used to meet water demands for several days due to increased turbidity in Bull Run reservoirs. All groundwater served to customers meets or surpasses drinking water standards.

All water supplied by Portland's public water system meets or surpasses federal and state drinking water standards. The Portland Water Bureau performs approximately 54,400 analyses on 11,800 water samples each year. Samplers collect water from the watershed reservoirs, in-town reservoirs, the distribution system , groundwater and consumers' taps. Monitoring schedules for Bull Run water and groundwater follow federal and state regulations. Records of analyses are available to the public. 


Learn about the Radionuclide Rule, Chemical Monitoring Regulations and the Arsenic Rule.

Disinfection Byproducts

Read the Trihalomethane Rule (1990) and Stage 1 Disinfectants and Disinfection Byproducts Rule.

Ground Water Rule

Link to EPA rule to ensure drinking water quality from ground water.


Regulations that impact Portland's water supply.

Informing the Public

Read about rules that mandate annual information sharing efforts.

Lead & Copper

Find out how to reduce your exposure to lead.


Learn about the Total Coliform Rule and LT2.


Learn about the Information Collection Rule (1996) and the Unregulated Contaminant Monitoring Rule (2002).

Surface Water

Regulations affecting Portland's unfiltered source of water.