Monday - June 11, 2018

Drinking Water and Algal Toxins – Key Information for Lake Oswego and Tigard water customers

Recently, the City of Salem issued a drinking water advisory for cyanotoxins produced by blue-green algae that were detected at low levels in the City’s water. Media outlets have also released information stating that many utilities do not monitor for cyanobacteria or cyanotoxins because there is no current regulation for these contaminants. The Lake Oswego Tigard Water Partnership would like to share some key information with our customers on this topic.

No cyanotoxins have been detected in the City of Lake Oswego and Tigard Water Service Area’s drinking water. At this time, there are no major algae blooms reported in our water source, the Clackamas River.

The Lake Oswego Tigard Water Partnership participates in a voluntary blue-green algae monitoring program to monitor both the source water and the treated drinking water. Our staff currently collect samples for cyanotoxins twice a month and would increase this sampling if indication of toxin producing cyanobacteria are detected in reservoirs upstream of our water intake.

In partnership with the Clackamas River Water Providers, a coalition of water providers that get their water from the Clackamas River, the cities of Lake Oswego and Tigard fund and participate in a source water protection and monitoring plan for sampling and response to cyanotoxins. This plan is based on Best Management Practices and guidance from the Oregon Health Authority, Environmental Protection Authority, and American Water Works Association.

With recent upgrades, the Lake Oswego Tigard water treatment plant has robust treatment technologies that provide multiple barriers to remove algal toxins, including ozone treatment, biological filtration, and chlorine disinfection, ranked among the best technologies for reducing algal toxins.

The Partnership is committed to providing the communities of Lake Oswego and Tigard with high-quality drinking water from the Clackamas River, which meets and exceeds all federal and state drinking water standards.

For more information, about monitoring and testing for blue-green algae cyanotoxins in the Clackamas River visit:

For more information about Lake Oswego and Tigard’s water treatment process visit:

For Oregon Health Authority FAQs about algal blooms visit:

For additional questions, please contact the water treatment plant at 503-635-0394.