Starting today, March 12, the Portland Water Bureau will begin blending a small portion of water from its Columbia South Shore Well Field with water from the Bull Run Watershed as an annual maintenance operation.

Public notification is not required but the Portland Water Bureau informs the media and sensitive water users, as a practice, when it activates groundwater and when it has significant operational changes. The groundwater maintenance run is expected to be completed by March 21, when the Portland Water Bureau anticipates returning to 100 percent Bull Run water.

As a result of careful planning, Portland is fortunate to have access to two excellent water sources that allow us to be prepared to meet the range of supply and demand conditions that occur in the Portland water system.

The Columbia South Shore Well Field is a high-quality water supply that meets or surpasses all federal and state drinking water regulations.

The city's groundwater supply is a complex system composed of groundwater wells, pumps, treatment systems, electronic controls, and other equipment that must be operated regularly to identify maintenance needs. By doing this operation routinely, the bureau will ensure the reliability of the system when needed, either in an emergency or to meet seasonal supply demands.

The average contribution of groundwater to the system will be approximately 20 percent of the total daily water demand. Due to the low percentage of groundwater being blended with the Bull Run Source, the bureau does not expect there to be a noticeable change in water chemistry. It can take up to two weeks, depending on location and overall water demand, for the blended water to make its way through the distribution system to homes and businesses.

Customers with questions are encouraged to call the Water Line at 503-823-7525.

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