From Tuesday, August 4, 2020 through August 27, 2020, the Portland Water Bureau blended a portion of water from the Columbia South Shore Well Field into the distribution system as part of a maintenance operation. The groundwater supply is a complex system composed of pumps, chemical feed systems, electronic controls, and other appurtenances; it must be operated regularly to identify maintenance needs and issues. By doing this maintenance operation, the bureau will ensure the reliability of the system when needed, either in an emergency or as part of seasonal supply.
The groundwater system was operated for approximately 10 hours a day Monday through Friday at an approximate rate of 54 million gallons per day. The groundwater contribution to the system varied daily from zero to approximately 40 percent of the total daily water demand. On August 27th, the Portland Water Bureau returned to 100% Bull Run. Customers can expect it to take approximately two to ten days, depending on location and overall water demand, for the Bull Run water to make its way through the distribution system to homes and businesses. The table below is the approximate water quality of the blended water as well as the Bull Run and groundwater.
|Characteristic||100% Bull Run (1)||60% Bull Run/40% Groundwater||100% groundwater (2)||EPA/OHA standard|
|Temperature (degrees C)||14||14||15||N/A|
|pH (units)||8.2||8.2||8.2||6.5-8.5 (3)|
|Color (units)||8||<5||<5||15 (3)|
|Specific conductance (μmhos/cm)||32||92||182||N/A|
|Total dissolved solids (mg/L)||21||67||135||500 (3)|
|Silica (mg/L as Si)||4||10||20||N/A|
|Total organic carbon (mg/L)||0.9||0.5||<0.3||N/A|
|Total alkalinity as CaCO3 (mg/L)||9||43||94||N/A|
|Hardness as CaCO3 (mg/L)||7||32||69||250 (3)|
Last Updated: August 31, 2020
(1) Most recent values measured in Bull Run raw or treated water.
(2) Average value at the Groundwater Pump Station Outlet during 2019 supply operation.
(3) This is a secondary standard established by the EPA as a guidance to assist public water systems in managing drinking water for aesthetic considerations, such as taste, color and odor. These contaminants are not considered to present a risk to human health at this standard.
For more information about Portland’s drinking water quality, call the Water Quality Line at 503-823-7525.