Water will be drawn from the Willamette River near Wilsonville, treated at an advanced water treatment facility, and conveyed through earthquake-resilient pipes to TVWD customers.
Up to 350,000 Tualatin Valley Water District, Hillsboro, and Beaverton customers will begin receiving water from the Willamette Water Supply System as early as late-2026.
The new system will use the following six steps to ensure your water is high quality every day.
Step 1: Intake Facility. Fine screens keep debris like leaves, sticks, and rocks in the river and protect fish from entering the treatment facility. The screens are submerged deep in the river below the lowest observed river levels. From a concrete structure located on the riverbank, very large pumps move the water through seven miles of large pipeline to the water treatment plant.
Step 2: Sediment Removal. At the water treatment plant, special water treatment chemicals help collect silt and other contaminants together to form larger particles. Microsand is added to weigh the particles down and help them settle out of the water quickly.
Step 3: Ozone Treatment. Ozone gas bubbles are distributed to kill microorganisms and prepare the water for additional contaminant removal. Ozone treatment is effective at breaking down organics and improves water taste and odor. Excess ozone gas is destroyed before it can enter the environment.
Step 4: Filtration. The ozonated water passes through filter beds with deep layers of granular activated carbon and sand. The filters remove organic materials and chemical contaminants as well as the tiny particles that cause cloudiness.
Step 5: UV Light Disinfection. Following filtration, the water passes through ultra-violet (UV) light reactors where intense light destroys any remaining microorganisms. This type of disinfection is particularly effective against certain microorganisms (like bacteria and viruses) that can cause disease.
Step 6: Chlorine Disinfection. As the final treatment step, a small amount of chlorine is added to the water. Like most water agencies, we are required to disinfect the water as it leaves the treatment plant. This final treatment step effectively prevents the regrowth of microorganisms in the water as it travels through pipelines to your water provider.
