Drinking Water Treatment by the Portland Water Bureau
- How does the Portland Water Bureau treat its drinking water?
- Is my water treated by filtration?
- Does the Portland Water Bureau add fluoride to drinking water?
- Does the Portland Water Bureau treat for Cryptosporidium?
General Questions About Drinking Water Quality
- Is Portland’s water soft or hard?
- What is the pH of Portland’s water?
- Are sodium levels in Portland’s drinking water affecting my health?
- Is there radon in Portland’s drinking water?
- What is the temperature of my water?
Drinking Water Quality in the Home
- Who can I call about water quality or pressure concerns?
- What is the water pressure at my home?
- How can I get my water tested?
- Why is my water discolored?
- Why are there colored particles in my drinking water?
- Why is the color of my water sometimes different in the fall?
- What causes stains on sinks or plumbing?
- What can I do if I am sensitive to chloramines?
- What should I do if my water tastes or smells bad?
- What should I know before purchasing a home water filter or treatment device?
- Is it safe to use tap water in my fish tank?
Drinking Water Treatment by the Portland Water Bureau
Portland’s drinking water is treated to produce high-quality drinking water to meet all state and federal drinking water regulations. Treatment is a three-step process:
1. Disinfection: chlorine is added at the source to disinfect the water.
2. Chloramination/Disinfectant Stabilization: aqueous ammonia is added, which bonds with chlorine to form chloramines. Chloramines are a disinfectant that stays in water longer than chlorine.
3. pH Adjustment: sodium hydroxide is added to increase the pH of the water to reduce corrosion of lead and copper from plumbing systems.
More information can be found on the Water Bureau’s Source Water Treatment page.
No. Neither the groundwater nor Bull Run source water is filtered. The Bull Run source meets the filtration avoidance criteria of the Surface Water Treatment Rule. The State of Oregon approved Portland’s compliance with these criteria in 1992. Portland continues to meet these criteria on an ongoing basis.
No. The Portland Water Bureau does not add fluoride to the water. Fluoride is a naturally occurring trace element in surface and groundwater. The U.S. Public Health Service and the Centers for Disease Control and Prevention consider the fluoride levels in Portland’s water sources to be lower than optimal for the prevention of tooth decay. You may want to consult with you dentist about fluoride treatment to help prevent tooth decay, especially for young children.
The Portland Water Bureau does not treat for Cryptosporidium. The Oregon Health Authority has issued Portland a variance from the LT2 rule treatment requirements for Cryptosporidium. The Portland Water Bureau continues to meet the state-mandated conditions of the variance by testing for Cryptosporidium, maintaining watershed protections, and conducting field inspections and environmental monitoring. More information can be found on Portland's Treatment Variance page.
General Questions about Drinking Water Quality
Portland’s water is very soft. The hardness of Bull Run water is typically 3-8 parts per million (ppm) – approximately ¼ to ½ a grain of hardness per gallon. Portland’s groundwater hardness is approximately 80 ppm (about 5 grains per gallon), which is considered moderately hard.
The pH of Portland’s drinking water typically ranges between 7.4 and 8.1. For more information about measuring pH at your own home, including troubleshooting tips, please see our Measuring pH in Portland’s Drinking Water page.
There is currently no drinking water standard for sodium. Sodium is an essential nutrient. Sodium in Portland’s water typically ranges between 2 and 9 ppm, a level unlikely to contribute to adverse health effects.
Radon is a naturally occurring radioactive gas that cannot be seen, tasted or smelled. Radon is rarely detected and only at extremely low levels from the Bull Run source. The Bull Run supplies over 90 percent of Portland’s drinking water. Radon has been regularly detected in the Columbia South Shore Well Field, Portland’s back-up water source. In Portland, groundwater is only used for brief periods of time, and is usually blended with water from the Bull Run. Based on the historical levels of radon in Portland’s drinking water, it is unlikely to contribute to adverse health effects. For more information, visit the Portland Water Bureau’s Radon webpage. Additional information about radon can be found at the EPA’s Radon webpage or by calling the EPA Radon Hotline at 800-SOS-RADON.
Most of the year, Portland gets its water from two reservoirs in the Bull Run Watershed resulting in water temperatures that vary throughout the year along with the seasons. In general, Portland’s drinking water temperature can vary between 38 and 75 degrees Fahrenheit.
Drinking Water Quality in the Home
The Water Line, 503-823-7525 or WBWaterLine@portlandoregon.gov, can answer your questions and concerns about water quality or pressure. The Water Line is available 8:30 am – 4:30 pm Monday-Friday. If you have an emergency after these hours, please contact the after-hours number at 503-823-4874.
The Portland Water Bureau provides water to all services with a minimum pressure at the water meter of 20 pounds per square inch (psi). Most homes receive water at a pressure of 40-80 psi. We monitor pressure throughout the system. Pressure concerns are usually a result of an issue on the customer side of the supply line. For example, older galvanized pipes can corrode internally and reduce the flow to household faucets, and leaks can cause a loss of pressure. To learn more about pressure visit our Flow and Pressure page, our Troubleshooting Water Pressure & Flow Issues page, or call the Water Line at 503-823-7525 to find out what range of pressure is delivered to your meter. Your water meter also has a leak detector built into it – use this Portland Water Bureau Leak Detection brochure to help you find out if you have a leak.
The Portland Water Bureau provides free lead-in-water testing. Contact the LeadLine online or at 503-988-4000 to request a lead-in-water test kit. For more extensive testing, private laboratories can test your tap water for a fee. Not all labs are accredited to test for all contaminants. For information about accredited labs, call the Oregon Health Authority, Oregon Environmental Laboratory Accreditation Program at 503-693-4122.
When the water from your faucet is discolored this indicates a disturbance in the water main. Since Portland is an unfiltered water system, there is a fine layer of sediment on the bottom of the water mains. These sediments can be stirred up by hydraulic disturbances caused by hydrant use, valve turning, main breaks or adjacent construction and cause the water to be discolored. Usually the water will clear on its own within a few hours. If your water is discolored:
For more information about discolored water, visit the Water Bureau's Discolored Water page.
Particles in water are usually mineral deposits or indicate the dip tube in your hot water heater is disintegrating. To test if particles in your water are plastic or minerals, place the particles in vinegar. Minerals will dissolve in the vinegar, plastic from a dip tube will not.
The dip tube is a long tube inside the water heater. It connects to the cold water pipe at the top of the heater and takes the cold water down to the base of the water heater to the heating element. The dip tube flecks are not toxic or harmful.
The majority of water heaters made in the 1990's utilized a dip tube made of plastic (PVC) that can break down. It starts to break down from the bottom and over time the flecks get into your pipes. Particles can be white, blue/green (from copper pipes) or reddish (from galvanized iron pipes). The particles can clog faucets with screens, hot water hoses connected to appliances, and shower heads. A shorter dip tube also makes the water heater use more energy since more cold water is entering at one time.
To replace your dip tube, follow manufacturer instructions. Plumbers can replace dip tubes and flush the hot water heater.
Please feel free to call the Water Line at 503-823-7525 if you have any other questions.
Portland Water Bureau customers may notice a slight color change in the drinking water at their tap in the fall. This change in color is typical for the Bull Run supply during the fall. This is a normal, seasonal variation in our unfiltered water supply.
The pale tint is due to the seasonal lowering of reservoirs in Bull Run. We start each summer with the reservoirs brim-full, and then use from this stored supply until the rains come again in the fall.
As a result, the two large lakes that are the Bull Run reservoirs are lower in the fall than at other times of the year. Throughout the summer, leaves and other organic matter are being washed into the reservoirs and act like tea leaves, adding color to the water. The color is from tannins in the organic matter. This is harmless and only affects the appearance of the water; it does not affect the taste or the quality.
Stains or colored films and residue can be a result of bacteria or an interaction with different metals in household plumbing. While the stains may be bothersome, your water will usually still be safe to drink and use. Regular cleaning with common household cleaners can control stains on sinks or plumbing fixtures. Common stains and their causes include:
If you are concerned about the amount of metals that your household plumbing is contributing to your drinking water, you may choose to order a free test kit which tests for five metals: lead, copper, iron, manganese, and zinc. To order your free test kit, contact the LeadLine online or at 503-988-4000.
Even at low levels, some customers may be sensitive to chloramine (chlorine + ammonia), which is used to treat Portland’s drinking water. Customers with a sensitivity may experience skin or eye irritation, or they may notice a chlorine taste or odor when others do not. Customers may choose to purchase shower and faucet filters that remove chloramines.
The Portland Water Bureau uses chlorine and ammonia to disinfect Portland's water in a process called chloramination. Chloramines can be lethal to fish. Check with a local pet store to determine if you need to dechlorinate your water or for other precautions you may need based on your household plumbing and variety of fish.