What Do Newspapers and Water Have in Common?

by Bob Castle

Las Gallinas Valley Reclamation Plant

Like bottles, cans, and paper, water can be recycled too. MMWD recycles up to two million gallons of water a day at our Las Gallinas Valley Reclamation Plant. The water we recycle is wastewater that has been treated by the Las Gallinas Valley Sanitary District. At our recycled water treatment plant we filter it and treat it further so that it meets the most stringent standards in the United States for recycled water. The finished water is crystal clear, odorless, and free of harmful bacteria. It is similar in quality to swimming pool water.

The recycled water is then distributed via a separate pipeline system to 350 customers in northern San Rafael, Terra Linda, and Marinwood who use it for irrigation, toilet flushing, and other non-drinking purposes. Using recycled water for these purposes saves over 900 acre-feet of potable water annually—enough to meet the needs of 2,700 MMWD households for one year.

With our limited water supplies, the use of recycled water might appear to be a panacea. However, the biggest obstacle to expanded use of recycled water is cost. Recycled water requires a separate distribution system to avoid the possibility of cross-connections with potable water. Our current system required the construction of 25 miles of pipeline, 3 storage tanks, and 4 pump stations, in addition to retrofitting each customer’s private irrigation system to separate it from the potable system. Significantly expanding the recycled water distribution system could be twice as expensive as desalination, another water source being considered by MMWD.

Despite the challenges, we continue to explore ways to increase the use of recycled water. This year we are designing an expansion of the distribution system to bring recycled water to the Peacock Gap Golf Course in San Rafael.

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A Brief History of Recycled Water in MMWD

by Bob Castle

Construction of Las Gallinas Valley Reclamation Plant (1989)

This weekend the Las Gallinas Valley Reclamation Plant, MMWD’s two-million-gallon-per-day (MGD) recycled water treatment facility, will celebrate its 20th birthday. The plant was dedicated October 17, 1989—just hours before the Loma Prieta earthquake struck. (Fortunately the new plant came through unscathed.)

MMWD’s water recycling program dates back even further to the drought of 1976-77 when a pilot plant, built in 1975, was used for drought relief. We completed a permanent one-MGD treatment plant in 1981 in partnership with the Las Gallinas Valley Sanitary District. The 1989 dedication marked the doubling of the plant’s production capacity to two-MGD. 

Traditionally, recycled water is used for landscape irrigation. In order to make the most efficient use of the treatment facility and distribution system, MMWD pioneered the use of recycled water for other purposes. In fact, our north San Rafael service area is home to:

• The first air-conditioning cooling tower in California to use recycled water
• The first car wash in California to use recycled water (Betts Marin Car Wash)
• The first commercial laundry in the United States to use recycled water (Nazareth House)
• The first use of recycled water for a single family residence in Northern California (Northview Development)
• The first penal institution to use recycled water for toilet flushing (Marin County Jail)

To help pave the way for an expanded use of recycled water in Marin and around the state, MMWD initiated several pieces of legislation that authorized new uses of recycled water. The new laws resulted in the creation of low-interest loans to fund water recycling projects;  the ability for public agencies to require dual plumbing in new construction so that toilets can be flushed with recycled water; and the authorization of dual plumbing systems for office buildings, theaters, auditoriums, schools, hotels, apartments, barracks, condominiums, dormitories, jails, and prisons.

Today, Marin has about 20 buildings that use recycled water to flush toilets and urinals—more than anywhere else in the US except for Irvine, California (40 buildings).

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