On Wednesday, April 20, the Portland Water Bureau will begin adjusting the alkalinity of the Bull Run source water at the Lusted Hill Treatment Facility. Alkalinity will be adjusted to an approximate target of 25 mg/L as Calcium Carbonate (CaCO3). This compares to the naturally low alkalinity of the Bull Run that can vary from 5 – 10 mg/L. The increased alkalinity levels should be entering the distribution system Wednesday afternoon and may take up to two weeks to reach all locations in the system. The increase in alkalinity increases the buffering capacity of the water which will allow for a more stable and consistent pH of the water.
This adjustment is the first step in bringing our improved corrosion control treatment online that is anticipated to adjust the Bull Run source water to an alkalinity of 25 mg/L and a pH of 8.6. This improved treatment will be brought online in steps to allow the distribution system to adjust to these changes and minimize any water quality impacts. We will be closely monitoring the distribution system water quality during these changes and anticipate the following steps to meet the treatment targets:
April 20, 2022: Begin alkalinity adjustment from natural Bull Run alkalinity of 5 – 10 mg/L to a target of approximately 25 mg/L.
Late May 2022: Increase pH from current target of 8.3 to 8.5.
Late June 2022: Further increase pH to anticipated target of 8.6
Additional adjustment of alkalinity or pH may be made depending on the effectiveness of initial treatment targets to reduce levels of lead at customer taps.
We will continue to notify you prior to each step above. These treatment changes are only for the Bull Run source. We will not be adjusting the pH or alkalinity of the Columbia South Shore Well Field. This will continue to have an approximate alkalinity of 100 mg/L and a pH of 8.2, that can vary based on the blend with the Bull Run source and the wells in operation.
For more information, visit portland.gov/water/bullruntreatment/corrosion-control.
If you have any questions, please do not hesitate to call the Water Quality Line at