Water mains present infrastructure issues to Town of San Anselmo


Henry Pratt

Water main break causes temporary street and residential flooding on Mountain View Ave. outside Archie Williams.

Four instances of water main breaks have occurred in San Anselmo since April, resulting in road closures, extensive repairs and frustration from community members. Some of these piping systems are not only old, but falling into disrepair. To understand why pipe bursts are so frequent, one must understand the history of water systems in the town.

The State of California established the Marin Municipal Water District [MMWD] in 1912, shortly after building the first water pipelines in West Marin. Marin has an incredibly complex water system, which is one of the oldest public systems in California. Many pipes in the area are still the originals, some over 120 years old. 

Sir Francis Drake Boulevard had its first minor flooding event of the year on April 28 due to a water main break. The MMWD shut down Saunders Ave from 10 a.m. to 7 p.m. that day. A line across the street burst a few months later on Aug. 22, causing more emergency repairs and road detours. 

Water main rupture on Brookside Dr. Nov 5. floods the street outside of San Anselmo homes. (Henry Pratt)

Two recent breaks brought further light onto the issue of pipe ruptures, one on Oak Springs Dr on Oct. 10 and the other on Brookside Dr Nov. 5

“[There was] a lot of water running down the street in front of our house,” said resident Kevin Lozaw, whose home on Brookside Dr was near the main break on Nov. 5. “I had to stay away from where they were working into the night.”

Each time a pipe ruptures, MMWD workers devote hours of work to fix them, causing road damage, detours, and frustration from the community.

“This past summer and fall, there were three water main breaks near Archie Williams, which is a lot in a short time period…This caused huge traffic delays for thousands of motorists, as well as closing the AWHS main parking lot through lunch,” said Scott Schneider, Assistant Public Works Director with the Town of San Anselmo. “The town has requested that the [Marin Municipal] Water District review their system along Sir Francis Drake Boulevard.”

Brookside Ave. a few months after the water main break and street repair. (Ella Furuichi)

The ten-inch-wide pipe beneath Sir Francis Drake Blvd. connects to 908 miles worth of transmission water piping controlled by the MMWD. The water system also includes over 90 separate pump stations, which move water at a faster pace. 

“When you have… a lot of miles of infrastructure, and the infrastructure is aging, it is a continuing process of maintenance and repair,” said former Marin Water Board Director Larry Bragman. 

The older pipes in the area were constructed out of cast iron, a metal used for its strength and longevity. Although these pipes have a life expectancy of 50 to 100 years, cast iron pipes can become susceptible to corrosion and wall breakages as they age. Recently, the MMWD added electronic anti-corrosion stations, which are units that take rust and corrosion out of pipes, hoping to slow down the influx in necessary repairs. 

The MMWD has an ongoing Capital Improvement Program (CIP), with planned repairs and replacements throughout the County. Although pipe ruptures have occurred more frequently over the past year, previously scheduled repairs to pipes are, in fact, more frequent. 

Since the spring of 2020, the CIP has replaced pump stations, improved anti-corrosion methods, and continued pipeline replacements. Their most recent repair on Barber Avenue replaced a 120-year-old corroded cast iron pipe with 440 feet of new welded steel pipelines.

“The older the pipe is, [the more] they are subject to some corrosion. As the iron pipe ages, it becomes more brittle,” Bragman said. “Even small Earth movements can cause a rupture and at that point, we need to do an emergency repair to avoid losing water from the system.” 

Pipe rupture on Saunders Ave. in April left small cracks in the pavement after flooding lifted the street. (Ella Furuichi)

The Town of San Anselmo and MMWD recently began their attempt to work in tandem. San Anselmo shares future road plans with MMWD so the two can rebuild the old pipelines and fix the roads at the same time. This way, the Water District won’t excavate a newly-paved  . 

“The coordination has worked well, and the Water District has replaced water lines on Butterfield Road, the Morningside neighborhood, on San Francisco Boulevard and surrounding streets over the last several years, with the town coming in afterwards to pave or slurry seal the streets,” Schneid said. 

Despite this partnership, a few belated repairs and new ruptures have resulted in a need to excavate newly-paved streets, such as  the failed replacement and eventual rupture on Saunders Ave in April. Schneider reports that frequent construction in neighborhoods often leads to residents’ frustration. 

Despite inconveniences caused by the pipes, the aging system has provided neighborhoods with water for 20 years longer than their life expectancy. As new and improved technology is added to the San Anselmo area, ruptures and breaks should become a rare issue.