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Water Treatment Plant
Lake Oswego's drinking water originates in the Clackamas River watershed.
The Lake Oswego Tigard Water Treatment Plant produces high quality drinking water for more than 100,000 customers every day. Lake Oswego's drinking water is made clean and safe using a state-of-the-art treatment process known as conventional filtration, plus ozone. Take a look inside the heart of the water treatment process.
With recent studies predicting a major earthquake occurring in the Pacific Northwest sometime within the next 50 years, the Lake Oswego Tigard Water Partnership took steps to ensure the survivability of its drinking water system. By requiring each of the new water supply facilities to be designed and constructed to remain functional after a 9.0 magnitude earthquake, we have improved our odds of bouncing back quickly from a significant seismic event. Learn about the design features that will help keep water flowing soon after an earthquake.
The City of Lake Oswego is now an official partner with the U.S. Geological Survey-led ShakeAlert© Earthquake Early Warning System—bringing a powerful new layer of protection to the Lake Oswego–Tigard Water Treatment Plant and its staff.
Interested in learning more about your drinking water? Take a behind-the-scenes tour of the Lake Oswego-Tigard Water Treatment Plant, located in West Linn!
Tours are held about once a month between spring and summer, take approximately 1 ½ hours and are limited to 15 people per tour.
Clean drinking water is an essential resource we rely on every day. Providing residents and businesses in Lake Oswego with safe, dependable, high-quality water is our top priority.
Lake Oswego’s tap water meets or exceeds every State and Federal standard for safe drinking water. Get to know your drinking water by reviewing the latest 2025 Water Quality Report.
Here are some tips on how to prepare for an emergency, how to treat water in an emergency, and how to prevent, prepare, and respond to freezing or burst pipes.
The Water Management and Conservation Plan for the City of Lake Oswego and the City of Tigard was created to document the development and implementation of water management and conservation policies and programs that ensure sustainable water use for the community members of both cities.
Water Treatment Plant: (503) 635-0394