MMWD Cleaning Its Pipes

Don't worry too much about the water spewing from the fire hydrant down the street. The Marin Municipal Water District says it's all part of a plan.

Water district officials began its annual water main flushing program in southern Marin this month. The program continues through April 19 in Larkspur, Corte Madera, Mill Valley, Belvedere and Tiburon.

Watching the water spill onto the streets might seem like a waste, but water district officials say it would be difficult to capture the water in a water truck or other container since the water must be released at such a high velocity to effectively scour the water mains.

The flushing will occur between 8 a.m. and 2:30 p.m. and takes about 15 minutes for each hydrant. Approximately 100-200 gallons of water are released per minute. Only selected hydrants are opened along the main line and the water is allowed to flow into the storm drain.

"We release as little water as possible, but the focus is on maintaining water quality and protecting public health," according to MMWD spokesperson Elisa Ignatius. "It is not cost-effective to capture the water and return it to the treatment plant."

The flushing is recommended by the California Department of Health Services to clear transmission and distribution pipelines of sediment that can impair the quality of drinking water. The State mandates the water district flush 20 percent of its water mains annually to preserve water quality.

The process is usually carried out at night to minimize disruptions to service and street traffic. The water district will perform this year's flushing in the morning and afternoon in an attempt to curb overtime expenses for the crews.

District officials warn residents may notice slight pressure drops, air in the lines or “dirty” water in their own plumbing. Officials suggest residents limit water use during periods of flushing and then run the taps for a short time to clear the pipes.

Flushing was performed in San Rafael earlier in the week and is scheduled for the following areas beginning next week through April 19:
 
March 15: Along Magnolia Ave. and in Madrone Canyon in Larkspur, and along Sir Francis Drake Blvd. in Larkspur and Greenbrae

March 22: In Corte Madera along Tamalpais Dr. and Tamal Vista Blvd., Summit Dr. and Redwood Ave. (the Christmas Tree Hill neighborhood), and Camino Alto/Corte Madera grade; and the Underhill Rd. area of Mill Valley

March 29: Along Paradise Dr. in Corte Madera and lower Summit Ave. in Corte Madera; along Sir Francis Drake Blvd. in Greenbrae

April 5: Along Paradise Dr. in Tiburon from Trestle Glen Blvd. up to downtown Tiburon

April 12: Downtown Tiburon and upper Tiburon along Gilmartin Dr. through Hacienda Dr.; upper section of Belvedere along Golden Gate Ave. through Bella Vista Ave.

April 19: Lower section of Belvedere from Bay View Ave. down; upper section of Lyford Dr. in Tiburon and the Hill Haven area of Tiburon