By Steve Isaacs

The Marin Municipal Water District Board of Directors just decided on our “path to resiliency” by approving a pipeline to bring water from the Russian River in Sonoma County.

As a director and co-founder of the Marin Coalition for Water Solutions group, I can say our members thank the board for this step, as it will help. However, it won’t completely solve the problem.

The pipeline will provide a limited amount of water under contract with the Sonoma County agency. Hopefully, the contract will be lived up to, but Marin will be one of several subcontractors dependent on that water. Our group’s concern is that, in the event of a multi-year drought (like the one we just experienced), Sonoma Water may decide it can’t send Marin what it needs. It is unclear what happens in that scenario. That’s a big problem.

Relying so heavily on the pipeline puts too many eggs into one basket. We will be depending too much on North Bay rainfall. True, MMWD has other projects in mind to help improve our supply, but all research shows they’ll have little impact.

To be clear, the pipeline is a good step. Our group hopes it gets completed quickly. But the board should also aggressively pursue a longer-term, drought-proof alternative — water reuse.

At the end of 2023, the state passed new rules and regulations on what needed to be done to take wastewater (the water that goes down the drain or flushed down the toilet) and treat it to drinkable standards so it can be distributed directly to homes and businesses. This is a huge deal and can be the long-term solution to our supply quandary.

For over 40 years, the water district serving Orange County has been providing purified wastewater to their customers. Other cities in Texas and New Mexico have done the same. Mickey Chaudhuri, the treatment and water quality manager for the Metropolitan Water District of Southern California (the wholesale water purveyor with about 19 million customers), says that the new rules will be a gamechanger for water districts threatened with chronic or periodic droughts.

“Regardless of whether it is wet or dry, you’ve got a source of supply through recycled water,” Chaudhuri said in an article published by the LAist news website last year. “You’re able to better manage the weather extremes.”

Don’t forget: Recycled, treated water must meet the stringent standards set up by the state.

In Marin we don’t have the ability to move and store large amounts of wastewater, so our water reuse will have to be direct potable reuse (DPR). This approach requires treatment plants to clean the water. Unfortunately, in Marin, that’s not possible right now.

Our recycling plants would have to be modified and upgraded through a lengthy process. That’s why the Marin Coalition for Water Solutions feels that MMWD should do a pilot project to prove the feasibility of the concept.

In their planning documents, it has already identified the Central Marin Sanitation Agency (CMSA) and the Sewerage Agency of Southern Marin as candidates for DPR, but the recent discussions have left these viable alternatives off the table. This direction is inconsistent with the momentum toward water reuse that is evident in coastal communities throughout California.

Water reuse projects in California take many years to bring to full scale implementation. The first step is to design and build a pilot facility at the wastewater treatment plant to demonstrate the quality of the product to the customers. MMWD and CMSA completed a DPR study recently that shows the potential water supply is equal to what it has been importing from Sonoma County. A pilot project at CMSA in partnership with MMWD makes a lot of sense as a first step toward drought-proof water resiliency that Marin needs.

We encourage MMWD to take the steps necessary to initiate such a pilot project.

Steve Isaacs, of Greenbrae, is the co-founder of a water-focused group of concerned Marin residents. Learn more at MarinCoalitionforWater Solutions.com