Safe drinking water is essential to all Portlanders and Portland businesses. Drinking water regulations are developed to protect public health and maintain high quality drinking water. Compliance with drinking water regulations ensures we provide safe and reliable drinking water for all of Portland and our wholesale customers.

To meet regulations, the Portland Water Bureau (PWB) routinely measures for over 200 contaminants in our source waters and throughout the distribution system. Contaminants we test for include Cryptosporidium, bacteria, lead, and a wide range of compounds. Failure to comply with drinking water regulations can have wide ranging impacts to Portland, ranging from Portlanders having a reduced confidence in the safety of their drinking water to issuing a boil water notice or needing to install additional water treatment.

Portland is fortunate to have two excellent sources of drinking water – the Bull Run Watershed and the Columbia Southshore Well Field. Portland has rigorous source water protection programs as a key step in maintaining compliance with drinking water regulations. Water quality is also carefully managed through the treatment process and into the distribution system with more than 4,700 water samples collected each year. In 2022, improved corrosion control treatment launched to reduce lead at the tap.

Additional improvements in lead levels are expected with the installation of filtration. PWB continues to meet all aspects of the bilateral compliance agreement with the Oregon Health Authority, including watershed protection, monitoring, reporting, outreach and adhering to a schedule for Cryptosporidium treatment. In 2027, a new filtration plant is scheduled to come online to treat for Cryptosporidium, reduce other contaminants and provide more consistent water quality.

Over 240 samples a month are collected throughout the distribution system to ensure bacterial contamination is not present. Any samples showing bacterial growth require follow up sampling and if more than 5% of samples in a month are positive, PWB must identify and correct any possible causes. In 2025, less than 1% of samples tested each month were positive for possible bacterial growth and no samples tested positive for E.coli well below established safety thresholds. Only detections of E.coli pose a health risk and could result in a violation if the detection is confirmed by a positive follow-up sample. PWB takes steps to actively manage water quality in the distribution system and minimize water age, including unidirectional flushing of the distribution system.

A dedicated Water Quality Line phone number (503-823-7770) serves all customers with questions or concerns and is continuously improving to better serve underrepresented Portlanders, by attending community events, providing access to translation services, and seeking customer feedback.

Data used for compliance with drinking water regulations are collected from the source water, through the treatment process, at the entry point to the distribution system, throughout the distribution system and at customer taps. Trained Water Bureau staff collect the water samples, most of which are analyzed by the Water Bureau’s in-house accredited laboratory that performs over 50,000 analyses per year. Data is then analyzed and reviewed by technical staff and validated data is submitted to the Oregon Health Authority.

• Read the Annual Water Quality Report, which provides important information about Portland's water system and drinking water quality over the past year.
• Visit our water quality overview page to learn about Portland's water quality programs, testing protocols, and ongoing initiatives to protect public health.
• Access Portland's drinking water test results to view detailed laboratory analyses and water quality monitoring data.
• Review regulatory compliance data submitted to the Oregon Health Authority to see how Portland's water system meets or exceeds state and federal standards.