For the majority of our customers living in or near Burlington, Mount Vernon, and Sedro-Woolley, your drinking water comes from Judy Reservoir, a 1.45 billion-gallon reservoir located above Clear Lake.

Your Drinking Water

Skagit PUD fills Judy Reservoir with water diverted from four creeks in an uninhabited, nine-square-mile forested area in the Cultus Mountain watershed. Water is also pumped up from a diversion station on the Skagit River to Judy Reservoir during critical periods or when the streams run low. As demand requires, we transfer water from Judy Reservoir to the adjacent water treatment plant, which went into service in 1990. The treatment plant is staffed around the clock by certified water treatment plant operators.

The treatment process begins with primary disinfection using chlorine dioxide. Then, operators add agents to cause small particles to combine into larger clusters that can be more easily settled and filtered from the water, a process called coagulation and flocculation. The water passes through anthracite coal and sand filters, removing suspended particles and impurities. After leaving the treatment plant, the pH is adjusted, and the water is disinfected using chloramines — formed when ammonia is added to chlorine to treat drinking water. Chloramines provide longer-lasting disinfection as the water moves through pipes to customers. The levels of additives are monitored constantly to ensure proper dosages are maintained.

Initially, the treatment plant was designed to produce about 18 million gallons of drinking water daily. Skagit PUD expanded its capacity in 2009 to handle 30 million gallons of water daily. Treated water flows to the Skagit Valley customers through two major transmission lines that are part of the 600 miles of pipelines that serve PUD customers.