Marin Water advances $1.1M pipeline replacement amid board debate on recycled water network expansion

Marin Water advances $1.1M pipeline replacement amid board debate on recycled water network expansionA fire flow improvement project in Kentfield prompted directors to question when the utility should begin laying unconnected recycled water pipes to build out its future network, despite state separation requirements that can double trenching costs.

The district reviewed the $1.1 million Palm Avenue Pipeline Replacement Project, which will install 1,730 feet of steel pipe to replace infrastructure dating back to 1937.

Staff deemed laying recycled water pipe during the project financially unfeasible, noting it would double the project cost due to Title 22 trench separation rules.

Directors pushed for a more proactive approach to installing recycled water infrastructure during open-trench projects to gradually close a nearly 4-mile gap to the nearest facility.

The district is coordinating the pipeline installation with a Marin County road resurfacing project to reduce pavement restoration requirements.

The Marin Municipal Water District's Planning Committee reviewed the Palm Avenue Pipeline Replacement Project on July 28, advancing a $1.1 million initiative to replace aging, fire flow-deficient piping in the unincorporated community of Kentfield, California. The project will install approximately 1,730 feet of new 6-inch and 8-inch welded steel pipe to replace cast iron and asbestos concrete infrastructure installed as early as 1937. To optimize costs, the district is coordinating the installation with an upcoming Marin County road resurfacing project. The county has agreed to waive the district's standard resurfacing requirements, allowing the utility to perform plug pavement restoration while the county handles the full-depth roadway restoration. During the project review, the board engaged in a strategic debate regarding the district's long-term recycled water buildout. Directors questioned whether the utility should opportunistically lay recycled water piping in the open trench to support its 2040 Water Resources Master Plan. Staff explained that installing recycled water lines alongside the potable water replacement would nearly double the overall project cost. This financial barrier is driven by Title 22 water main separation requirements regulated by the State Water Board, which mandate a separate trench. Furthermore, staff noted the nearest existing recycled water pipeline is 3.9 miles away, requiring extensive infrastructure to bridge the gap. Despite the immediate cost constraints, multiple directors advocated for a more proactive approach to laying "purple pipe" for future use. One director argued that the distance to existing facilities will never decrease unless the district begins putting pipe in the ground, suggesting the utility should install dry pipes now to shorten future connection distances. Chair Larry Russell acknowledged the historical complexities of recycled water planning, citing past instances where local commercial developments were dual-plumbed but never received recycled water connections due to infrastructure delays. The district will open construction bids for the Palm Avenue project on July 30, with a formal contract award recommendation expected at a future board meeting.