Contra Costa Water District Completes Autumn Canal Inspections and Los Vaqueros Water-Quality Audits

Water-quality chemists and civil engineers with the Contra Costa Water District (CCWD) have completed their late-October round of reservoir blending adjustments, treatment plant calibrations, and structural inspections along the 48-mile Contra Costa Canal serving Martinez, Pleasant Hill, Concord, Pacheco, and Clayton. Presented to the CCWD Board of Directors at district headquarters on Concord Avenue in October 2026, the autumn operational audit confirms that drinking-water reserves entering the 2026–2027 winter water year meet or surpass every state and federal health benchmark. CCWD supplies treated and untreated water to roughly 520,000 residents across central and eastern Contra Costa County.

During late autumn—when natural freshwater outflows from the Sacramento–San Joaquin Delta reach their seasonal low before winter mountain snows and rains begin—tides can push higher-salinity bay water eastward toward CCWD's river intakes at Rock Slough, Old River, and Mallard Slough. To keep tap water crisp and low in sodium and chloride, district operators blend Delta diversions with high-quality water stored earlier in the year inside the 160,000-acre-foot Los Vaqueros Reservoir in the hills south of Brentwood.

At the Randall-Bold and Bollman water treatment plants in Oakley and Concord, laboratory technicians also verified advanced ozone disinfection and granular activated carbon filtration systems that remove naturally occurring organic compounds. Meanwhile, field crews patrolled the Contra Costa Canal right-of-way through Concord, Pleasant Hill, Walnut Creek, and Martinez to clear autumn leaf debris from siphon grates and inspect perimeter safety fencing along the East Bay Regional Park District's paved Contra Costa Canal Trail.

Diablo Valley ratepayers can request free residential water-use efficiency surveys, apply for smart-irrigation controller rebates, or download the latest water-quality report online at ccwater.com or by calling (925) 688-8000.