Heavy rains, like the record-breaking rainfall Portland experienced on Monday, left some Portlanders with questions about their drinking water. The storm and flooding does not affect the drinking water system. The Bureau of Environmental Services manages the City of Portland’s sewer and stormwater system. Your drinking water, provided by Portland Water Bureau, is carried in different pipes that are under constant pressure. This keeps any material from entering our drinking water system.
During very heavy rain storms, some combined sewage can overflow to the Willamette River and Columbia Slough. Water from the Willamette River and Columbia Slough is not your drinking water. Portland’s primary water source is the rain-fed Bull Run Watershed, located 26 miles east of Portland. The water is treated with chorine and ammonia to disinfect the water of any potential natural contaminants. However, Portland’s drinking water is not filtered, and large storms can result in an increase in sediment in the Bull Run. When this happens, Portland also has a secondary supply, groundwater from the Columbia South Shore Wellfield, to provide safe drinking water to our customers.
Since Portland is an unfiltered drinking water system, at times you may notice a slight tint to your drinking water. This color is not related to heavy rainfalls within the Portland Metro area but can occur seasonally or if there is work being done in your area.
If you have questions about your drinking water, contact the Drinking Water Line at 503-823-7525 or WBWaterLine@portlandoregon.gov (8:30 a.m. to 4:30 p.m. Monday-Friday) or visit our Water Quality at Home web page. For emergencies, call our hotline at 503-823-4874, 24 hours, 7 days a week.