EBMUD taking action on lingering effects of drought

District takes steps to stem formation of disinfection byproducts, maintain high quality drinking water.

California’s historic drought, followed by record-setting rainfall, continues to have impacts on drinking water systems throughout the San Francisco Bay Area. The East Bay Municipal Utility District is experiencing water quality and treatment challenges due to reduced water consumption, higher temperatures, and higher concentrations of organic materials in our untreated ‘raw’ water from Pardee Reservoir.

While EBMUD drinking water quality remains in full compliance with all state and federal regulations, the District is taking action to address elevated levels of disinfection byproducts.

In our regular collection and analysis of water samples throughout the distribution system, the District has seen a rise in the concentration of trihalomethanes (THMs) – disinfection byproducts formed when chlorine reacts with naturally-occurring organic matter in water—over the past few years.

The increase can be attributed to changes in the composition and amount of natural organic matter in EBMUD’s water supply. To address this challenge, the District has increased water quality sampling, implemented operational changes and a new flushing program. EBMUD is also piloting an aeration system at the Lafayette Water Treatment Plant to strip out THMs. In addition, long-term infrastructure upgrades to address this challenge are already underway.

This past November, EBMUD configured a pilot water treatment facility to test new treatment processes, doses and configurations. EBMUD is using this testing facility to evaluate different coagulants and filter configurations to address these water quality challenges.

The District is flushing pipes in areas most affected by these conditions. Flushing removes sediment and mineral deposits, and helps maintain a chlorine residual within the distribution system to ensure the delivery of high quality water to customers. Customers in Orinda and Berkeley have been notified via Nextdoor about flushing in their neighborhoods.

Reduced Water Consumption and Disinfection Practices 

Reduced water consumption – a tremendous benefit for EBMUD’s water supplies and future water needs – has reduced flows and water use in our systems. Reduced use can result in increased water age – the amount of time water remains in our pipes and storage tanks. Water age, along with water chemistry changes, can reduce the effectiveness of our disinfection practices – the treatment that removes water borne pathogens from our drinking water.

Flushing moves water through the distribution system, removes sediment and mineral deposits that can accumulate in water pipes, and helps maintain our high water quality throughout the drinking water system.