Portland, OR Water Quality Report
Sources Of Drinking Water in Portland, Oregon
Where does Portland get its water from? Most of your tap water begins as rainfall in the Bull Run Watershed, located about 30 miles east of Portland. Despite its proximity to Mount Hood, none of Portland's drinking water originates from Mount Hood, as the watershed is separated from the mountain by a significant geologic ridge. Some water comes from the city's groundwater supply, which the bureau uses as a secondary water supply.
The Portland Water Bureau operates a well field capable of producing close to 100 million gallons per day of high quality drinking water. The Columbia South Shore Well Field (CSSWF) is the second largest water source in the State of Oregon, with about half of the daily capacity of Portland’s Bull Run source. Groundwater from the CSSWF is used as a secondary source for customers served by the Bull Run supply and also provides supplemental supply during the summer high demand season. Is Portland's water safe to drink?
Source: City of Portland
Contaminants Found in Portland's Water Supply
(Detected above health guidelines)
Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.
Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).
Total trihalomethanes (TTHMs)
Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform.
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems. The fluoride that is added to water is not the naturally occurring kind, the main chemicals used to fluoridate drinking water are known as “silicofluorides” (i.e., hydrofluorosilicic acid and sodium fluorosilicate). Silicofluorides are not pharmaceutical-grade fluoride products; they are unprocessed industrial by-products of the phosphate fertilizer industry (Gross!). Since these silicofluorides undergo no purification procedures, they can contain elevated levels of arsenic — more so than any other water treatment chemical. In addition, recent research suggests that the addition of silicofluorides to water is a risk factor for elevated lead exposure, particularly among residents who live in homes with old pipes.
Potential Health Effects of Consuming These Contaminants
Health risks of Arsenic in excess of the health guidelines
Cancer: The health guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
Health risks of Chromium (hexavalent) in excess of the health guidelines
Cancer: The health guideline of 0.02 ppb for chromium (hexavalent) was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
Health risks of Total trihalomethanes (TTHMs) in excess of the health guidelines
Cancer: The health guideline of 0.8 ppb for trihalomethanes was defined by the California Office of Environmental Health Hazard Assessment as a draft public health goal, the level of drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
Health risks of fluoride in excess of health guideline
No standards exist for fluoride in water but fluoride is considered by many to be a neurotoxin.
Contaminant Levels Compared to Other Regions
- Health Guideline: 0.004 ppb
- National: 1.33 ppb
- State: 2.37 ppb
- Portland, OR: 0.435 ppb
- Health Guideline: 0.02 ppb
- National: 0.782 ppb
- State: 0.236 ppb
- Portland, OR: 0.0362 ppb
Total Trihalomethanes (TTHMs)
- Health Guideline: 0.8 ppb
- State: 22.9 ppb
- National: 23.4 ppb
- Portland, OR: 23.4 ppb
- Legal Limit: 4 ppb
- State: 0.244ppb
- National: 0.440 ppb
- Portland, OR: 0.0750 ppb
A hiker, blogger, and water quality expert...
- April Jones