We test Portland’s drinking water to make sure it meets all state and federal standards. Every year, water quality specialists regularly use about 90 sampling stations around the city to collect over 11,000 water samples. Our lab analysts conduct more than 49,000 water quality tests on those samples at our water quality laboratory. We regularly report results to the Environmental Protection Agency (EPA), the State of Oregon, and the public. The most comprehensive of those reports are posted on this page.
Annual Water Quality Report
See test results from 2022 in our Annual Water Quality Report. We test our water for over 200 regulated and unregulated contaminants in drinking water and give results in the report.
Supplemental water quality data
For customers who need water quality data beyond what is included in our annual water quality report, we provide additional water quality results three times per year. This report includes more detailed pH, fluoride, hardness, temperature, and other data than what you would find in the Annual Water Quality Report.
Two sources: Bull Run and groundwater
We have two sources of drinking water: surface water from the Bull Run Watershed and groundwater from the Columbia South Shore Well Field. We use groundwater, when needed, as a supplemental and emergency supply. We are currently serving 40% Bull Run water and 60% groundwater.
On Thursday, August 24, 2023, the Portland Water Bureau began adding groundwater from the Columbia South Shore Well Field to augment Portland’s main drinking water source, the Bull Run Watershed.This year’s dry spring and early start to summer weather, along with long-term weather forecasts, have resulted in the need for additional drinking water supply until the return of the fall rains. Most customers can expect to receive a blend of 40 percent Bull Run water and 60 percent groundwater from the Columbia South Shore Well Field. It can take up to two weeks, depending on location, for the blended water to make its way through the distribution system to homes and businesses.
This table shows a comparison of typical groundwater and Bull Run water quality. We say “typical” because actual conditions can change some of these numbers. Water quality can change based on many factors, including the time of year, the user’s location within Portland’s distribution system, water demand, and which wells we’re using when we use groundwater.
|Characteristic||100% Bull Run1||40% Bull Run/60% groundwater||100% groundwater2||EPA/OHA3 standard|
|Temperature (degrees C)||15||16.2||17||N/A|
|Specific conductance (µmhos/cm)||70||170.2||237||N/A|
|Total dissolved solids (mg/L)||44||107.6||150||5004|
|Silica (mg/L as Si)||4.3||13.18||19.1||N/A|
|Total organic carbon (mg/L)||0.8||0.4||<0.3||N/A|
|Total alkalinity as CaCO3 (mg/L)||30||72||100||N/A|
|Hardness as CaCO3 (mg/L)||7||48.4||76||2504|
1. Most recent values measured in Bull Run raw or treated water.
2. Average value at groundwater pump station outlet.
3. Oregon Health Authority
4. This is a secondary standard established by the EPA as a guideline 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.
As agreed upon in the Bilateral Compliance Agreement with the Oregon Health Authority, we test for Cryptosporidium from the Bull Run raw water intake. Individual detections for the current month of monitoring as well as a summary of the previous 12 months can be found below.
The table below is updated:
- Within 24 hours of each Cryptosporidium detection;
- Weekly, for a month following the most recent detection; or
- Monthly, when there have been no detections for over a month. Generally updated around the 15th of the following month.
Table of Cryptosporidium test results
|Test dates||Number of samples tested||Number of positive samples||Total Number of oocysts detected||Total Liters of water tested (approximate)|
|Sept. 1-13, 2023||16||0||0||400|
|August 1-31, 2023||17||3||3||550|
|July 1-31, 2023||9||0||0||450|
|June 1-30, 2023||10||0||0||500|
|May 1-31, 2023||19||2||2||950|
|April 1- 30, 2023||17||4||4||850|
|Mar. 1-31, 2023||17||2||4||850|
|Feb. 1-28, 2023||16||10||25||800|
|Jan 1-31, 2023||19||18||85||950|
Table of Cryptosporidium test results by year
|Test dates||Number of samples tested||Number of positive samples||Number of oocysts detected||Liters of water tested (approximate)|
|Jan. 1-Dec. 31, 2022||179||46||79||7,980|
|Jan. 1-Dec. 31, 2021||200||33||58||8,600|
|Jan. 1–Dec. 31, 2020||185||39||52||8,450|
|Jan. 1–Dec. 31, 2019||179||41||50||8,450|
|Jan. 1–Dec. 31, 2018||271||15||19||7,690|
|Jan. 1–Dec. 31, 2017||378||35||43||11,510|
|Jan. 1–Dec. 31, 2016||208||0||0||5,370|
How we test for lead
Twice each year, the Water Bureau tests for lead and copper in water collected from a group of over 100 homes that have lead solder and are more likely to have higher levels of lead in water. Homeowners collect water samples following EPA-recommended collection instructions after the water has been standing in the household plumbing for more than six hours. When samples are returned to us, we make sure they meet the regulatory requirements before being sent to the lab. This ensures that results from all the samples analyzed by the lab are in compliance with the Lead and Copper Rule.
If more than 10 percent of homes have lead levels over 15 parts per billion (ppb)—the action level established by the EPA to monitor the effectiveness of corrosion treatment—we notify our customers and perform outreach and education to those most at risk from lead exposure.
Lead testing results
Below is a graph and table with lead results from these homes. When the 90th percentile result is above 15 ppb, this means that more than 10 percent of homes are over 15 ppb and therefore above the EPA's action level. The results from 1992 were before the Water Bureau started corrosion control treatment. These results were above EPA's action level and required the Water Bureau to treat the water to reduce lead levels. We started treating the water for lead in 1997. Results that were above the EPA's action level are above the red line in the graph and in bold in the data table. The Water Bureau conducted the required public outreach and education each time the 90th percentile result was above 15 ppb.
Graph of Portland Joint Monitoring 90th Percentile Lead Levels by Year
Table of Portland Joint Monitoring 90th Percentile Lead Levels by Year
|Year||90th percentile of lead (ppb) in Spring monitoring period||90th percentile of lead (ppb) in Fall monitoring period|
Perfluoroalkyl and polyfluoroalkyl substances (PFAS)
The Portland Water Bureau is closely tracking news about detections of PFAS in drinking water around the country as well as the EPA’s newly proposed PFAS drinking water regulations. Fortunately, Portland’s drinking water is at low risk for PFAS, and PFAS have not been detected in drinking water from the Bull Run Watershed and the Columbia South Shore Well Field. We will continue to monitor our drinking water sources for PFAS and maintain our robust source water protection programs.
PFAS are a large group of human-made chemicals. PFAS have historically been used in a variety of ways, including in firefighting foams or to make consumer goods nonstick, water-repellent, or stain-repellent. Some of these chemicals are now known to be harmful to human health.
Around the country, PFAS contamination of drinking water sources has typically been traced to specific locations where large amounts of PFAS have been released into the environment over time. This includes industries that manufacture PFAS or apply PFAS to consumer goods, and facilities that use certain types of firefighting foam (which may include airports, military bases, and fire department training facilities).
Sources of PFAS near Portland’s drinking water supplies
There are no known sources of PFAS in or around our primary source of drinking water, the highly protected Bull Run Watershed.
We are aware of three sites in or near the Columbia South Shore Well Field that historically used PFAS-containing firefighting foams: Portland International Airport; Portland Air National Guard Base; and a Portland Fire and Rescue training facility. PFAS have been found in the shallow groundwater aquifers just below the surface at all of these sites. We do not get drinking water from these shallow aquifers where PFAS from these sites have been found.
The Portland International Airport and Portland Air National Guard sites are outside of the Columbia South Shore Well Field wellhead protection area and are currently believed to pose a low risk to Portland’s drinking water. The Portland Fire and Rescue training facility is within the Columbia South Shore Well Field but is also considered to pose a low risk to Portland’s drinking water. Drinking water from near the training facility location is drawn from deeper aquifers that are physically separated from the shallow aquifers by thick layers of silt and clay (these layers are called confining units). The PFAS in the shallow groundwater at this site are not expected to affect public water supplies. We have tested the deep well closest to the site, and it was free of PFAS. We will continue working to understand the extent of the shallow groundwater contamination at these sites and take the necessary steps to ensure Portland’s water supply remains protected.
PFAS drinking water test results
In 2014 and 2015, we tested for six types of PFAS in drinking water from the Bull Run Watershed and Columbia South Shore Well Field. The EPA required drinking water utilities around the country, including the Water Bureau, to test for these six PFAS as part the Unregulated Contaminant Monitoring Rule (UCMR 3). PFAS were not detected in any of the samples.
In 2018, we began voluntarily testing groundwater from a deep drinking water well adjacent to the Portland Fire and Rescue training site for twelve types of PFAS. PFAS have not been detected from this drinking water well. We continue to routinely test for PFAS at this well to confirm it remains safe.
In 2024 and 2025, we will be testing Portland’s drinking water from both sources for 29 types of PFAS. The EPA is requiring drinking water utilities across the country, including the Water Bureau, to test for these 29 PFAS as part of the Unregulated Contaminant Monitoring Rule (UCMR 5). The Water Bureau supports the EPA in requiring this type of testing, which helps the EPA understand the occurrence of PFAS in drinking water for communities across the country. Once the Water Bureau conducts its testing, results will be posted on this page as well as shared in our Annual Water Quality Report.
How we’re protecting Portland’s drinking water from PFAS
We are committed to protecting Portlanders’ health. Through our Groundwater Protection Program, we are taking active steps to protect Portland’s drinking water from PFAS contamination. These steps include:
- Monitoring and testing groundwater aquifers and the drinking water served to Portlanders;
- Working to identify potential PFAS sources in collaboration with the Oregon Department of Environmental Quality, which leads investigation and cleanup efforts of groundwater contamination sites;
- Regulating and providing technical assistance to facilities that manage hazardous materials within the Columbia South Shore Well Field. This helps prevent hazardous materials releases to groundwater; and
- Coordinating with Portland’s Bureau of Environmental Services to address emerging contaminant issues like PFAS across city programs.
What you can do about PFAS
You can help the City of Portland protect our streams, rivers, and groundwater from PFAS. We encourage you to learn more about how PFAS are used in household products. As consumers, we must be proactive and understand that purchasing products that contain PFAS and the day-to-day contact with these materials is a source of exposure and contributor to PFAS in the environment.
The best way to prevent PFAS from entering our streams, rivers, and groundwater is to remove the sources through product substitution and phasing out the use of products containing PFAS in industrial and manufacturing processes. In the Columbia South Shore Well Field, using chemicals responsibly is a major way you can protect the drinking water quality of Portland’s groundwater supply. Learn more on the Water Bureau’s How You Can Help Groundwater page, or attend one of our groundwater special events.
Your drinking water is treated with chlorine to kill harmful microorganisms and make the water safe to drink. After adding chlorine, we add ammonia to the water to form chloramines, which make chlorine last longer and protect public health. We routinely test chlorine levels throughout the city and seasonally adjust how much chlorine is added to the water. Our target chlorine levels range between 2.2 milligrams per liter (fall and winter) and 2.5 milligrams per liter (spring and summer). We do not have additional chlorine boosters in the distribution system.
Chlorine and health
The level of chlorine in your drinking water is safe to consume. Adding chlorine is one of the most common and cost-effective ways to protect public health from waterborne diseases. Chlorine has been used in Portland since the early 1900s, and chloramine has been used as a secondary disinfectant since 1957. We are required to meet strict drinking water standards regulated by the EPA and Oregon Health Authority. The EPA allows up to 4 milligrams per liter of chlorine in drinking water. The chlorine levels in Portland’s system are below this level.
Some people are more sensitive to the taste or smell of chlorine than others. Sensitive customers may choose to use a filter to remove chlorine taste and odor. People with skin sensitivities to chlorine or other health concerns should contact their health care provider.
Chlorine and aquatic animals or pets
You’ll need to remove chloramines for indoor or outdoor fish, reptiles, shellfish, and amphibians. You can buy safe treatment products, including granular activated charcoal filtration systems, dechlorinators, and water conditioner additives, at aquarium supply stores. Always follow product instructions.
Chlorine and plants or gardens
According to the Centers for Disease Control and Prevention, chloramine does not harm plants. Some people, however, use dechlorinator tablets to remove chloramines before applying water to plants or making compost teas.
The EPA sets standards (or limits) for substances in drinking water. Substances that have a standard set by the EPA based on health risk or aesthetic characteristics are called regulated contaminants. Unregulated substances do not have a drinking water standard, but the EPA may consider setting a standard for them in the future.
The EPA uses data from water utilities around the country to determine if substances should be regulated. Under the Unregulated Contaminant Rule (UCMR), the EPA requires Portland and approximately 6,000 other water utilities across the country to collect data for unregulated substances every five years. The EPA evaluates the test results and the potential health risks of the substances to determine whether they need to set a standard to protect public health.
Portland’s results: 2001–2003 unregulated substances monitoring
No UCMR 1 substances were detected in Portland’s drinking water.
Portland’s results: 2008–2010 unregulated substances monitoring
No UCMR 2 substances were detected in Portland’s drinking water.
Portland’s results: 2013–2015 unregulated substances monitoring
The following tables show the UCMR 3 substances detected in Portland’s drinking water.
Table of UCMR 3 results from treated drinking water entering the distribution system
|Substance||Minimum and maximum detected||Average detected||Likely source|
|Chlorate (ppm1)||<0.02 to 3.0||0.6||Byproduct of drinking water disinfection|
|Chromium (total) (ppb2)||<0.2 to 0.2||<0.2||Found in natural deposits|
|Chromium-6 (ppb)||<0.03 to 0.048||0.031||Found in natural deposits|
|Strontium (ppm)||0.01 to 0.074||0.026||Found in natural deposits|
|Vanadium (ppb)||0.27 to 2.9||0.84||Found in natural deposits|
Table of UCMR 3 results from treated drinking water throughout the distribution system
|Substance||Minimum and Maximum Detected||Average Detected||Likely Source|
|Chlorate (ppm)||<0.02 to 0.029||<0.02||Byproduct of drinking water disinfection|
|Chromium (total) (ppb)||<0.2 to 0.24||<0.2||Found in natural deposits|
|Chromium-6 (ppb)||<0.03 to 0.046||0.03||Found in natural deposits|
|Strontium (ppm)||0.01 to 0.019||0.015||Found in natural deposits|
|Vanadium (ppb)||0.28 to 0.36||0.32||Found in natural deposits|
About the UCMR 3 substances detected in Portland’s water
Chlorate, a byproduct of the drinking water disinfection process, can form when sodium hypochlorite is used as a disinfectant. The groundwater facility uses liquid sodium hypochlorite as a disinfectant. In July 2014, the level of chlorate from the Columbia South Shore Well Field groundwater treatment plant exceeded the EPA standard. As a result of the detections at the groundwater treatment plant, we changed how sodium hypochlorite is managed so that we can minimize the levels of chlorate in drinking water. Since only a small amount of affected groundwater was served and it was for a limited time period, the presence of chlorate is unlikely to contribute to adverse health effects.
Chromium is a naturally occurring element in rocks, animals, plants, soil, and volcanic dust and gases. Recent studies have shown that ingestion of drinking water or food containing chromium-6 may cause cancer in laboratory mice and rats. Total chromium (combined chromium-3 and -6) is currently regulated by the EPA at a maximum contaminant level of 100 parts per billion. At the very low levels detected in Portland’s drinking water, chromium-6 is unlikely to contribute to adverse health effects.
Strontium is a naturally occurring metal and is commonly found throughout the environment, including in drinking water. The current EPA health reference concentration indicates that ongoing exposure to strontium at levels of more than 4,000 parts per billion per day may lead to negative health effects. At the very low levels detected in Portland’s drinking water, strontium is unlikely to contribute to adverse health effects.
Vanadium is a metal found in the earth’s crust. Vanadium can dissolve into water that is in contact with natural deposits. The current EPA health reference concentration for vanadium indicates that ongoing exposure to vanadium at levels of more than 21 parts per billion per day may lead to negative health effects. At the levels found in Portland’s water, vanadium is unlikely to contribute to adverse health effects.
Portland’s results: 2018–2020 unregulated substances monitoring
The following table shows the UCMR 4 substances detected in Portland’s drinking water.
Table of UCMR 4 results
|Substance||Minimum and Maximum Detected||Average Detected||Likely Source|
|Manganese (ppm)||0.0017 to 0.0620||0.0173||Found in natural deposits|
|Total organic carbon (ppm)||0.89 to 1.70||1.37||Naturally present in the environment|
|Haloacetic acids-5 (ppb)||17 to 43||29.7||Byproduct of drinking water disinfection|
|Haloacetic acids-6Br (ppb)||<0.2 to 1.5||0.92||Byproduct of drinking water disinfection|
|Haloacetic acids-9 (ppb)||18 to 44||30.4||Byproduct of drinking water disinfection|
About the UCMR 4 substances detected in Portland’s water
Manganese is a metal found in the earth’s crust. It can dissolve into water that is in contact with natural deposits. Low levels of manganese in water can cause discolored water or staining. High levels of manganese can lead to negative health effects. At the levels in Portland’s water, it is unlikely to lead to negative health effects.
Total organic carbon is a precursor that is naturally present in the environment.
Haloacetic acids are disinfection byproducts. Disinfection byproducts form when precursors combine with chlorine, which is added to water as disinfection. High levels of disinfection byproducts could cause health problems in people. At the levels in Portland’s water, these are unlikely to lead to negative health effects.
The Water Bureau has proactively tested for radon for many years, although testing is not required by federal or state rules. Overall exposure to radon from Portland’s drinking water is very low. Radon is rarely detected from the Bull Run surface water, and when it is, it’s at extremely low levels. Radon from the Columbia South Shore Well Field’s Groundwater Pump Station outlet ranges from 131 to 390 pCi/L (picocuries per liter). We report radon results in the Annual Drinking Water Quality Report.
Radon in Portland’s drinking water does not pose a significant health concern. Radon is a naturally occurring radioactive gas that is a health concern when inhaled. As it moves up from the soil, it can be drawn into a home through the foundation and the gas can build to unsafe levels. The health risk from radon happens when high levels of radon in the home are breathed in. When present in drinking water, radon is generally not a health concern and is not currently regulated by the EPA or the State of Oregon.
How you can reduce your exposure to radon
In Portland, the greatest source of radon exposure is naturally occurring radon gas that enters homes and buildings through their foundations. If you’re concerned about radon exposure, you can order a radon test kit from the American Lung Association of Oregon. The EPA, US Surgeon General, and Oregon Health Authority all recommend testing your home for radon gas.
Cyanotoxins and algae
Cyanotoxins are a type of toxin, or harmful substance, produced by certain types of algae that grow in some lakes and rivers. There is only one group of algae, called cyanobacteria, that can produce toxins. Cyanobacteria are commonly found throughout the US in low numbers. However, cyanobacteria can become harmful to health when, under certain environmental conditions, toxin-producing cyanobacteria bloom and release toxins into the water. Not all cyanobacteria produce toxins and even those that are able to produce toxins do not always do so.
We test Bull Run source water for algae on a weekly basis. There are many types of algae detected in Bull Run source water, and they vary in type and amount throughout the year. Levels of algae that do not produce toxins increase on a seasonal basis. These types of algae do not pose a health risk, but can affect the taste or smell of the water, or clog home or building filters. We are fortunate that the Bull Run source water has never had cyanobacterial bloom and is not vulnerable to the environmental conditions that would encourage and support a cyanobacterial bloom.
We tested Bull Run source water for cyanotoxins in 2005 and the summers of 2018 and 2019. In 2005, a cyanotoxin was detected in one sample at 0.020 parts per billion, well below the current vulnerable population health advisory level of 0.3 parts per billion. All other test results did not detect cyanotoxins in the water.
State and federal rules that regulate cyanotoxins in drinking water
The State of Oregon requires some water providers at risk of cyanotoxins to routinely test their water. We are fortunate to have high-quality water sources and we are not a water system the state requires to test for cyanotoxins. Currently, there are no cyanotoxin rules at the federal level, but the EPA may regulate cyanotoxins in the future. Drinking water providers around the country are collecting data about cyanotoxins through the Unregulated Contaminant Monitoring Rule 4 (UCMR 4) to help the EPA decide if federal regulations are necessary.
Pharmaceutical and personal care products
Pharmaceuticals and personal care products are a broad group of substances. They include medicine (such as pain relievers, antibiotics, and birth control hormones) and consumer products (such as fragrances, lotions, and sunscreens). Trace amounts of these compounds have been found in water around the US. However, we regularly consume or expose ourselves to products containing these substances in much higher concentrations through everyday use of medicines and daily personal care routines. The level in which they can be found in drinking water sources is very small in comparison.
From 2006 to 2008, we tested both the Bull Run and Columbia South Shore Well Field drinking water supplies for several medications and chemicals used in consumer products. After several rounds of testing, medications and chemicals were not detected in most of the water samples. However, one sample tested from the Bull Run drinking water supply contained caffeine, and eleven samples tested from the groundwater drinking water supply contained caffeine or a medication, which included over-the-counter pain relievers, birth control hormones, antidepressants, and antibiotics. All compounds were detected at extremely low levels, measuring in parts per trillion. However, these findings are not conclusive: our quality control results indicate that there may have been sample contamination from the environment or the sampling and testing process.
The fact that a substance has been detected does not mean that the substance is necessarily harmful to humans—it simply means that a substance has been detected. The tests are extremely sensitive and can detect fractions of amounts that people are exposed to through everyday use. Most of our water samples did not show evidence of medications or chemicals. But even in ones that did, you would have to drink 400,000 gallons of Portland’s water to get the same amount of caffeine you would get in a cup of coffee.
How you can prevent medications and other compounds from entering the water
You can help by keeping unused medications out of the water supply. Most medications and over-the-counter drugs should not be flushed down the toilet or poured down the drain. The Oregon Health Authority’s Drug Take-Back and Disposal webpage has instructions for safely disposing of medications.