2023 Drinking Water Quality Report

A collage of images featuring Portland Water Bureau staff.
This annual report contains important information about Portland's drinking water and water system.
On this page

About this report

This is a past report from 2023.

Read our most recent Drinking Water Quality Report

Each year the Portland Water Bureau provides the Drinking Water Quality Report to all of its customers. The report is required by the State and the EPA and contains important information about Portland's drinking water and water system. The following 2023 Drinking Water Quality Report contains results from the 2022 calendar year. You can also read this report as a pdf: 

 Request a paper copy of the report

Portland’s drinking water sources and water system

A cartoon map showing Portland's water system that starts near Mt Hood on the right and goes through Portland to Washington Park on the left. The map shows a lake and two dams and reservoirs in the Bull Run Watershed, the two water treatment facilities, the Columbia South Shore Well Field, and underground pipes and reservoirs that carry and hold our drinking water around town.

Our drinking water sources

The Bull Run Watershed, Portland’s protected surface water supply, is in the Mount Hood National Forest, 26 miles from Portland. The Portland Water Bureau and the US Forest Service carefully manage the watershed to sustain and supply clean drinking water. In a typical year, the watershed receives an astounding 135 inches of precipitation (rain and snow), which flows into the Bull Run River and then into two reservoirs that store nearly 10 billion gallons of drinking water.

Source water assessments are completed to identify contaminants of concern for drinking water. For the Bull Run, the only contaminants of concern are naturally occurring microorganisms, such as Giardia, Cryptosporidium, fecal coliform bacteria, and total coliform bacteria. The Portland Water Bureau regularly tests Bull Run water for these microorganisms that live in virtually all freshwater ecosystems.

The Portland Water Bureau treats water to control organisms that could make people sick but does not currently treat for Cryptosporidium. Portland is installing filtration to remove Cryptosporidiumand other contaminants from drinking water by 2027. 

The Columbia South Shore Well Field, Portland’s protected groundwater supply,provides drinking water from 25 active wells located in three different aquifers. The well field is between Portland International Airport and Blue Lake Park. Portland uses the well field for two purposes: to supplement the Bull Run supply in the summer, and to temporarily replace the Bull Run supply during turbidity events, maintenance activities, and emergencies.

The Columbia South Shore Well Field is beneath homes and businesses with a variety of potential contaminant sources. The deep aquifers that are the primary sources of water supply have natural geologic protection from pollutants present at the land surface. Portland, Gresham, and Fairview work together to protect the well field. The cities’ Groundwater Protection Programs work with residents and businesses in the well field to ensure that pollutants from this urban area do not impact the groundwater source. Portland also hosts a number of groundwater education events.

Portland’s source water assessment is available online or by calling 503-823-7525.

Sign up for treatment and source water change notifications

The Clackamas River Water District, City of Gresham, City of Lake Oswego, City of Milwaukie, Rockwood Water People’s Utility District, Sunrise Water Authority, and Tualatin Valley Water District provide drinking water to some Portland customers who live near service area boundaries. Customers who receive water from these providers will receive detailed water quality reports about these sources in addition to this report.

Our drinking water system

  • Portland’s water system was established in 1895.
  • Portland’s drinking water system delivers water from two high-quality sources – the Bull Run Watershed and the Columbia South Shore Well Field – to almost one million people in Portland and surrounding communities.
  • Most of Portland’s drinking water comes from the Bull Run Watershed, 26 miles east of downtown Portland.
  • Treatment operators add chlorine to control microorganisms, such as bacteria and viruses, that could make people sick.
  • Treatment operators add ammonia to form a longer-lasting disinfectant. They also add sodium carbonate and carbon dioxide to reduce corrosion of metals.
  • Drinking water flows by gravity from Bull Run to Portland.
  • Pumps pull groundwater from the aquifers of the Columbia South Shore Well Field.
  • Reservoirs and tanks store water for everyday use, plus firefighting and emergency needs.
  • Water Bureau employees collect and test more than 11,000 water samples each year.
  • More than 2,200 miles of water mains carry water beneath the city’s streets.
  • Thousands of hydrants safeguard the city.

Investments in our water sources keep safe water flowing

Portland has a long history of careful planning and smart investments to make sure clean, safe water is flowing every time you turn on your faucet.

A black and white photo of teams of horses pulling carts loaded with massive pipes through the forest.
Six-up horse teams and drivers delivering conduit pipe in 1893.

Our commitment began in the late 1800s when Portlanders were getting sick from drinking untreated water from the Willamette River. To keep residents for future generations safe, we laid the first pipes from the Bull Run Watershed to the city and started serving clean drinking water to Portland in 1895.

Fast forward to the 1980s. We made another investment in the resilience of our water system by drilling our first groundwater well. This created an additional source of drinking water that could be used during long dry summers or when the Bull Run is not available. In 2022, this investment in a supplemental groundwater system allowed us to provide clean, safe drinking water to nearly one million people despite two extreme weather events that impacted our Bull Run supply: a summer and fall of record-breaking hot, dry temperatures and an atmospheric river of rainfall in November that resulted in increased turbidity in the Bull Run supply. 

Old photo of two men - one is wearing amazing red and white plaid pants - standing in a muddy area looking at pipes coming out of a groundwater pump in the ground. Water is splashing out of the pipes and onto the ground.
Exploratory well testing in 1976.

Today we continue this legacy of providing safe drinking water for future generations. We are now investing in a new Bull Run water filtration facility that will further improve our ability to respond to storms, treat for Cryptosporidium or other naturally occurring organisms that exist in the watershed, and further reduce lead levels at the tap. Together, the filtration facility and groundwater will allow us to stay flexible and adapt, providing water to the Portland region under any circumstances.

Frequently asked questions about water quality

What test results will I find in this report?

The Portland Water Bureau monitors drinking water for over 200 regulated and unregulated contaminants. This report lists all of the regulated contaminants the bureau detected in drinking water in 2022. If a known, health-related contaminant is not listed in this report, the Portland Water Bureau did not detect it in drinking water.

How is Portland’s drinking water treated?

Currently, Portland’s drinking water treatment is a three-step process: 1) Chlorine disinfects against organisms, such as bacteria and viruses, that could otherwise make people sick. 2) Ammonia stabilizes chlorine to form a longer-lasting disinfectant. 3) Sodium carbonate and carbon dioxide reduce the corrosion of metals such as lead. Portland’s treatment will have additional improvements in the coming decade.

Is Portland’s water filtered?

No. Neither of Portland’s sources is filtered. In response to a series of low-level detections of Cryptosporidiumin Bull Run water since 2017, Portland is installing a filtration plant to treat for Cryptosporidium. Bull Run water will be filtered by 2027.

Does the Portland Water Bureau add fluoride to the water?

No. Fluoride naturally occurs in Portland’s water at very low levels. You may want to ask your dentist or doctor about supplemental fluoride for preventing tooth decay. This is especially important for young children.

Is Portland’s water soft or hard?

Bull Run water—Portland’s main water supply—is very soft. It typically has a total hardness of 3–8 parts per million (ppm), or ¼ to ½ a grain of hardness per gallon. Portland’s groundwater supply is moderately hard: about 80 ppm, or about 5 grains per gallon.

What is the pH of Portland’s water?

The pH of Portland’s drinking water typically ranges between 8.0 and 9.0.

Has Portland tested its drinking water for PFAS?

Yes, and fortunately PFAS have not been detected in drinking water from either of our water sources. PFAS – perfluoroalkyl and polyfluoroalkyl substances – are a group of chemicals that are a growing concern for consumers and water providers across the country. The Portland Water Bureau shares this concern and is taking steps to protect and monitor our water for PFAS. Find out more at our PFAS and drinking water page.

How can I get my water tested?

For free lead-in-water testing, order a kit from the LeadLine or 503-988-4000. For other testing, you can pay a private, accredited laboratory to test your tap water. Information about accredited labs in Oregon can be found online or by calling 503-693-4100.

What causes temporarily discolored water?

Sediment and organic material from the Bull Run Watershed settle at the bottom of water mains. These can sometimes be stirred up during hydrant use or a main break. They can also be seen in the fall as a harmless tea-colored tint. Discolored water can also be caused by older pipes in buildings that add rust to the water. Find out more at our discolored water page

How should property managers maintain water quality in large buildings?

Managers of large buildings should implement a water management program to protect their water quality and address the risk of Legionella growth. This is especially important for healthcare facilities and residential buildings for people 65 or older. Find more at our water quality in large buildings page.

I have a water quality or water pressure question not answered here or need more assistance. Where can I find more information? 

Headshot photos of Portland Water Bureau staff, Lillian and Matt.
Lillian and Matt, our Water Quality Line staff, are happy to assist you with any water quality questions you may have.

You can start by checking out our troubleshooting guides for discolored water, low water pressure or high water pressure, tastes or odors in drinking water, and measuring pH in our water. You can also contact our Water Quality Line

Preparing for wildfires, one bucket of ash at a time

A collage of four photos. The top photo is of a wildfire burning bright orange at night. The next photo is of a person in a previously burned forest scooping wildfire ash with a shovel. The next photo is of a person in a lab setting pouring ash into a glass bottle filled with water. The last photo is of a person in a lab setting using lab equipment to test water.
(1)Bolt Creek Fire – WA, Oct 2022 [wildfire.gov]. (2) Minnekhada Park Fire – Vancouver, BC, Oct 2022 [Metro Vancouver]. (3) Water Quality Assistant Paul adds ash to Bull Run water. (4) Engineer Mojtaba tests filtered water at the test filtration facility.

As climate change increases the frequency of hotter and drier summers, communities in the Pacific Northwest are increasingly impacted by wildfires. Although the risk of fire in the very wet forests of the Bull Run continues to be low, the affect to water quality could be significant. Preparing for those impacts is a necessity. One way that we are preparing is by leading a research partnership of water providers, academic researchers, and industry experts to understand how our water treatment systems can filter wildfire ash out of drinking water.

Research is underway at our mini-filtration facility. Ninety-five buckets of wildfire ash from Vancouver BC, Washington, and Oregon were shipped to Portland for testing. Our team is mixing ash in Bull Run water, then running it through the filtration process to test how that treatment removes ash from water.

We are also partnered with the cities of Medford and Grants Pass, who experienced wildfires in 2020. Their experience of how they recovered their water infrastructure after the fires will provide valuable insights for all water utilities in the region.

The outcomes from this research are an important part of Portland’s wildfire planning. This research will show how to build our full-scale filtration facility so that it is more resilient to wildfire impacts. After an emergency, this will also help our treatment operators know how to respond and more quickly return to serving clean and safe drinking water from the Bull Run.

Contaminants detected in 2022

What the EPA says can be found in drinking water

Two white men are in a lab setting testing water with laboratory equipment.

Across the United States, the sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity.

In order to ensure that tap water is safe to drink, the Environmental Protection Agency (EPA) has regulations that limit the amount of certain contaminants in water provided by public water systems and require monitoring for these contaminants. Food and Drug Administration regulations establish limits for contaminants in bottled water, which must provide the same protection for public health.

Contaminants in drinking water sources may include microbial contaminants, such as viruses, bacteria, and protozoa from wildlife; inorganic contaminants, such as naturally-occurring salts and metals; pesticides and herbicides, which may come from farming, urban stormwater runoff, or home and business use; organic chemical contaminants, such as byproducts from industrial processes or the result of chlorine combining with naturally occurring organic matter; and radioactive contaminants, such as naturally occurring radon.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline at 800-426-4791 or at EPA's drinking water website.

Definitions of acronyms used in data tables

  • MCL: maximum contaminant level. The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
  • MCLG: maximum contaminant level goal. The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
  • MRDL: maximum residual disinfectant level. The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
  • MRDLG: maximum residual disinfectant level goal. The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.
  • N/A: not applicable. Some contaminants do not have a health-based level or goal defined by the EPA, or the MCL or MCLG does not apply to that result.
  • NTU: nephelometric turbidity unit. A unit for measuring the turbidity, or cloudiness, of a water sample.
  • ppm: parts per million. Water providers use ppm to describe a small amount of a substance within the water. In terms of time, one part per million is about 32 seconds out of one year.   
  • ppb: parts per billion. Water providers use ppb to describe a very small amount of a substance within the water. In terms of time, one part per billion is about 3 seconds out of one hundred years.
  • pCi/L: picocuries per liter. Picocurie is a measurement of radioactivity.
  • TT: treatment technique. A required process intended to reduce the level of a contaminant in drinking water.

Data tables of contaminants detected in 2022

Data table of regulated contaminants detected in Portland's untreated source water
Regulated contaminantMinimum detectedMaximum detectedEPA standard: MCL or TTEPA standard: MCLGSources of contaminant
Turbidity (NTU)0.254.745N/AErosion of natural deposits
Fecal coliform bacteria
(% >20 colonies/100 mL in 6 months)
Not detected0.6%10%N/AAnimal wastes
Giardia (#/L)Not detected0.04TTN/AAnimal wastes
Data table of regulated metals and nutrients detected in Portland's treated water at the entry point
Regulated contaminantMinimum detectedMaximum detectedEPA standard: MCL or TTEPA standard: MCLGSources of contaminant
Arsenic (ppb)<0.501.05100Found in natural deposits
Barium (ppm)0.000740.010722Found in natural deposits
Copper (ppm)<0.000500.000651.31.3Found in natural deposits
Fluoride (ppm)<0.0250.1544Found in natural deposits
Nitrate (as nitrogen) (ppm)<0.0100.141010Found in natural aquifer deposits, animal wastes
Nitrite (as nitrogen) (ppm)<0.0050.00711Found in natural aquifer deposits, animal wastes
Total nitrate + nitrite (as nitrogen) (ppm)<0.0100.151010Found in natural aquifer deposits, animal wastes
Data table of regulated microbial contaminants detected in Portland's treated water in the distribution system
Regulated contaminantMinimum detectedMaximum detectedEPA standard: MCL or TTEPA standard: MCLGSources of contaminant
Total coliform bacteria
(% positive per month)
Not detected0.4%TTN/AFound throughout the environment
Data table of regulated disinfection residuals and byproducts detected in Portland's treated water in the distribution system
Regulated contaminantMinimum detectedMaximum detectedEPA standard: MCL or TTEPA standard: MCLGSources of contaminant
Total chlorine residual (ppm)
running annual average
1.872.014 [MRDL]4 [MRDLG]Chlorine used to disinfect water
Total chlorine residual (ppm)
range of single results at all sites
0.502.73N/AN/AChlorine used to disinfect water
Haloacetic acids (ppb)
running annual average at any one site
14.130.360N/AByproduct of drinking water disinfection
Haloacetic acids (ppb)
range of single results at all sites
<2.028.9N/AN/AByproduct of drinking water disinfection
Total trihalomethanes (ppb)
running annual average at any one site
15.226.480N/AByproduct of drinking water disinfection
Total trihalomethanes (ppb)
range of single results at all sites
1.631.9N/AN/AByproduct of drinking water disinfection
Data table of unregulated contaminants detected in Portland's treated water
Unregulated contaminantMinimum detectedAverage detectedMaximum detectedSources of contaminant
Manganese (ppm)0.00120.01930.0318Found in natural deposits
Radon (pCi/L)<12167333Found in natural deposits
Sodium (ppm)3.410.615Found in natural deposits  

Looking for additional data? Find it on our Drinking Water Test Results page.

About These Contaminants

Arsenic, barium, copper, fluoride, and manganese

These metals are elements found in the earth's crust. They can dissolve into water that is in contact with natural deposits. At the levels found in Portland’s drinking water, they are unlikely to result in negative health effects. 

Fecal coliform bacteria

To comply with the filtration avoidance criteria of the Surface Water Treatment Rule, water is tested for fecal coliform bacteria before disinfectant is added. The presence of fecal coliform bacteria in source water indicates that water may be contaminated with animal wastes. This is reported in percent of samples with more than 20 colonies in 100 milliliters of water during any six-month period. The Portland Water Bureau uses chlorine to control these bacteria.


Wildlife in the watershed may be hosts to Giardia, a microorganism that can cause gastrointestinal illness. The treatment technique is to remove 99.9 percent of Giardia cysts. The Portland Water Bureau uses chlorine to control Giardia.

Haloacetic acids and total trihalomethanes

Disinfection byproducts form when chlorine interacts with naturally occurring organic material in the water. High levels of disinfection byproducts can cause health problems in people. Portland adds ammonia to form a more stable disinfectant, which helps minimize disinfection byproducts.

Nitrate and nitrite (as nitrogen)

Nitrate and nitrite, measured as nitrogen, can lead to bacterial and algal growth in the water. At levels that exceed the standard, nitrate and nitrite can contribute to health problems. At the levels found in Portland’s drinking water, nitrate and nitrite is unlikely to result in negative health effects.


Radon is a naturally occurring radioactive gas that cannot be seen, tasted, or smelled. Radon can be detected at very low levels in the Bull Run water supply and at varying levels in Portland’s groundwater supply. Based on the historical levels of radon in groundwater combined with the limited amount of groundwater used, people in Portland are unlikely to have negative health effects from radon in water. Find more information about radon from the EPA.


There is currently no drinking water standard for sodium. At the levels found in drinking water, it is unlikely to result in negative health effects.

Total chlorine residual

Total chlorine residual is a measure of free chlorine and combined chlorine and ammonia in the water distribution system. Chlorine residual is a low level of chlorine remaining in the water and is meant to maintain disinfection through the entire distribution system.

Total coliform bacteria

Coliforms are bacteria that are naturally present in the environment. Coliform bacteria usually do not make people sick. They are used as an indicator that other potentially harmful bacteria may be present. If more than 5 percent of samples in a month are positive for total coliforms, an investigation must be conducted to identify and correct any possible causes. The Portland Water Bureau uses chlorine to control these bacteria.

We are required to monitor your drinking water for specific contaminants on a regular basis. Results of regular monitoring are an indicator of whether or not your drinking water meets health standards. During July 2022, we did not complete all monitoring or testing for coliform bacteria, and therefore cannot be sure of the quality of your drinking water during that time. In July 2022, we tested 238 water samples for coliform bacteria, not meeting our requirement of testing at least 240 samples per month. We returned to compliance the following month. The Portland Water Bureau updated our coliform testing plans to ensure that we are consistently meeting requirements.


Turbidity is the cloudiness of a water sample. In Portland’s system, increased turbidity usually comes from large storms, which suspend organic material in Bull Run water. Increased turbidity can interfere with disinfection and provide an environment for microorganisms to grow. Since the Portland Water Bureau does not yet filter Bull Run water, the treatment technique is that turbidity cannot exceed 5 NTU more than two times in 12 months. When turbidity rises in the Bull Run source, Portland switches to its Columbia South Shore Well Field source.

Reducing exposure to lead and investing in public health

What to know about lead

The Portland Water Bureau cares about the health of the families in our community and is committed to helping you reduce your exposure to lead. If present, lead at elevated levels can cause serious health problems, especially for pregnant people and young children.

Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The Portland Water Bureau is responsible for providing high-quality drinking water but cannot control the variety of materials used in plumbing components in homes or buildings. Lead is rarely found in Portland’s source waters and there are no known lead service lines in the water system. In Portland, lead enters drinking water from the corrosion (wearing away) of household plumbing materials containing lead. These materials include lead-based solder used to join copper pipe — commonly used in homes built or plumbed between 1970 and 1985 — and brass components and faucets installed before 2014.

In Portland, the most common sources of lead exposure are lead-based paint, household dust, soil, and plumbing materials. Lead is also found in other household objects such as painted antique furniture, barro pottery, cultural cosmetics (sindoor, kumkum, tikka, roli, and kohl), and turmeric purchased overseas.

What you can do

When your water has been sitting for several hours, such as overnight or while you are away at work or school, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. If you are concerned about lead in your drinking water, you can request a free lead-in-water test from the LeadLine (503-988-4000). Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from EPA’s Safe Drinking Water Hotline: 800-426-4791.

Additional steps to reduce exposure to lead from plumbing

Photo of a kitchen faucet that is filling a glass of water.
  • Run your water to flush any lead out.
  • Use cold, fresh water for cooking, drinking, and preparing baby formula.
  • Do not boil water to remove lead.
  • Test your child's blood for lead.
  • Test your water for lead.
  • Consider using a filter certified to remove lead.
  • Clean your faucet aerators every few months.
  • Consider replacing faucets or fixtures installed before 2014.

The LeadLine (503-988-4000) can help keep your family safe from lead.

Lead and copper test results from homes with higher risk of lead in water

The Portland Water Bureau offers free lead-in-water tests to anyone in the service area. Twice each year, the Portland Water Bureau also collects water samples from a group of over 100 homes that have lead solder and are more likely to have higher levels of lead in water. Testing results from 2022 were below the EPA action level.

Data table of lead and copper results from high-risk residential water taps
Regulated contaminantFall 2022 90th percentile resultsHomes exceeding action levelEPA standard: action levelEPA standard: MCLGSources of contamination
Lead (ppb)11.75 out of 108 (4.6%)150Corrosion of household and commercial building plumbing systems
Copper (ppm)0.1710 out of 108 (0%)1.31.3Corrosion of household and commercial building plumbing systems
  • 90th percentile: 90 percent of the samples results were less than the values shown.
  • Action level: The concentration of a contaminant which, if exceeded, triggers treatment or requirements of which a water system must follow. 
  • ppm: parts per million. Water providers use ppm to describe a small amount of a substance within the water. In terms of time, one part per million is about 32 seconds out of one year.   
  • ppb: parts per billion. Water providers use ppb to describe a very small amount of a substance within the water. In terms of time, one part per billion is about 3 seconds out of one hundred years.

Bull Run Treatment Projects: Investing in public health

Three mason jars filled with water and each jar has a different type of metal pipe in them. One jar has a piece of copper pipe with lead solder, one jar has a piece of lead pipe, and the last jar has a piece of brass pipe.
In 2020 and 2021, Water Bureau engineers tested Bull Run water in jars to determine the most effective corrosion treatment to use at the Bull Run Filtration facility.

Investing in safe, clean drinking water is one of our top priorities. To protect our community from lead and meet regulatory requirements, we have made investments in our drinking water treatment systems to reduce lead levels at the tap. The most recent treatment upgrade to address lead in drinking water came in 2022, and we anticipate an additional reduction of lead levels at the tap when our filtration facility comes online in 2027.

In April 2022, we began treating our drinking water with improved corrosion control. By increasing the water’s pH and alkalinity, the improved treatment better protects our water from lead in plumbing materials. Our team spent six months ramping up to full operation to give our drinking water system time to adjust to the changes in water chemistry. The treatment team continues to collect water samples from around the city to evaluate how the improved treatment affects lead levels. These results help us monitor the changes to the system and determine the correct treatment to reduce lead levels as much as possible.

This is a graphic with text showing a timeline of when the Portland Water Bureau has changed its drinking water treatment. A text version of this graphic is available at the end of the article.
Take a deeper dive: Portland’s drinking water treatment investments

Looking forward at our future water treatment investments, our next drinking water treatment upgrade is Bull Run Filtration, which is scheduled to be online in 2027. Even though the primary benefit of filtration is to remove Cryptosporidium and other potential contaminants, our testing shows that filtration combined with corrosion treatment will reduce lead levels even more. We look forward to continuing our work to further reduce lead levels at the tap.

Text version of graphic

Take a deeper dive: Portland's drinking water treatment investments

  • 1929: Started disinfection with chlorine
  • 1957: Started adding ammonia to help disinfection last
  • 1997: Adjusted pH to reduce lead levels
  • 2022: Adjusted pH and alkalinity to further reduce lead levels
  • 2027: Filtration will remove Cryptosporidium and further reduce lead levels

Learn more about our improved corrosion control treatment

Monitoring for Cryptosporidium and investing in our future

Cryptosporidium is a potentially disease-causing microorganism that lives in virtually all freshwater ecosystems. Drinking water treatment for Cryptosporidium is required by state and federal regulations. For five years, the Oregon Health Authority (OHA) did not require the Portland Water Bureau to treat for Cryptosporidium based on data showing that Cryptosporidium was rarely found in the Bull Run Watershed. In 2017, after the start of low-level Cryptosporidium detections, OHA determined that treatment is now necessary. Detections of Cryptosporidium from the Bull Run have continued, primarily during the rainy season.

The Portland Water Bureau does not currently treat for Cryptosporidium, but is required to do so under drinking water regulations. Portland is working to install filtration by 2027 under a compliance schedule with OHA. In the meantime, the Portland Water Bureau is implementing interim measures such as watershed protection and additional monitoring to protect public health. Consultation with public health officials continues to conclude that the general public does not need to take any additional precautions.

Exposure to Cryptosporidium can cause cryptosporidiosis, a serious illness. Symptoms can include diarrhea, vomiting, fever, and stomach pain. People with healthy immune systems recover without medical treatment. According to the Centers for Disease Control and Prevention (CDC), people with severely weakened immune systems are at risk for more serious disease. Symptoms may be more severe and could lead to serious life-threatening illness. Examples of people with weakened immune systems include those with AIDS, those with inherited diseases that affect the immune system, and cancer and transplant patients who are taking certain immunosuppressive drugs.

The Environmental Protection Agency has estimated that a small percentage of the population could experience gastrointestinal illness from Cryptosporidium and advises that customers who are immunocompromised and receive their drinking water from the Bull Run Watershed consult with their health care professional about the safety of drinking the tap water.

Data table of 2022 Cryptosporidium monitoring results at the raw water intake
Total number of samples testedTotal number of samples positive for CryptosporidiumMinimum concentration detected (oocysts/L)Maximum concentration detected (oocysts/L)
17946Not detected0.08

Special Notice for Immunocompromised Persons

A doctor is sitting in her office wearing a white coat and stethoscope. She is smiling a waving to someone she is video chatting with on her phone.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons, such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly people, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. Environmental Protection Agency (EPA)/ Centers for Disease Control and Prevention (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at800-426-4791.

Bull Run Treatment Projects: Investing in our future

A photo of a nurse in front of a hospital building.
Darcey Ayala (Nurse Manager Oregon Health & Science University Hospital) “Having clean and reliable source water is really impactful. We would not be able to provide lifesaving patient care without water.”

We are investing in a safe and abundant water future for our community with the Bull Run Filtration project. The long-term improvements we are planning will use filtration treatment to protect public health by removing Cryptosporidium and other potential contaminants from our Bull Run supply, filtering out sediment and organic material, and further reducing lead levels at the tap. This project will not only help us provide consistent high-quality drinking water but also make our water system more resilient to future risks.

A photo of a person in front of an espresso coffee machine.
Ian Williams (Owner of Deadstock Coffee and Concourse Coffee): “The filtration project is definitely important — having good, consistent filtered water is great. Shout-out to Portland for taking care of us.”

We are halfway through the 10-year project of designing and building this filtration facility. We are working to deliver the benefits of filtered Bull Run water by September 2027 and will begin construction in fall 2023. Good planning and preparation will help construction have a successful start and is part of our commitment to providing the best value to our ratepayers while we make these generational investments in the future of our water system.

What do business owners, nurses, and firefighters have in common?

They are all looking forward to the benefits of filtered Bull Run water. Watch our video to hear five community members share more about the future benefits of the Bull Run Filtration project.

What do business owners, nurses, and firefighters have in common? They are all looking forward to the benefits of filtered Bull Run water. Watch our video to hear five community members share more about the future benefits of the Bull Run Filtration project.

Learn more about our filtration project

A computer rendering of the future drinking water filtration plant. There are pools of water in the foreground, administrative buildings in the back, and green trees in the background.

Additional drinking water information

Additional drinking water information from Oregon Health Authority971-673-0405. Portland Water Bureau’s Water System ID: 4100657

The Portland Water Bureau is a member of the Regional Water Providers Consortium. Find out more about the Consortium and its work in water conservation, emergency preparedness, and regional coordination. 

Last updated: June 2023

Reports from previous years

2022 Drinking Water Quality Report

2021 Drinking Water Quality Report

All reports are available in Chinese, Russian, Spanish, and Vietnamese. Please call 503-823-7525 to request a translation of the report. Interpretation services are available.