Healdsburg benefits from an invaluable resource that keeps gardens, trees, and vineyards irrigated: free, non-potable water produced by its wastewater-reclamation facility. The plant recycles 350 million gallons of effluent drained and flushed in the city every year, according to city officials, or slightly more than half its annual water consumption. The reused H₂O is used in irrigation, construction, and other applications that require lower levels of treatment than drinking water. This eases pressure on regional reservoirs and wells while enlisting a wide pool of users in promoting an ethos of conservation, all the while helping manage the amount of treated wastewater discharged into the Russian River.

Currently, California treats and reuses approximately 728,000 acre-feet, or approximately 18 percent, of the yearly wastewater it produces. But the state has higher ambitions for increasing water security: New goals call for a near threefold increase by 2030 to 2 million acre-feet annually.

Backed by initiatives such as the California Water Board’s Clean Water State Revolving Fund and federal support, including a $750 million grant program, several large projects are in the pipeline. Orange County, for one, is upping capacity on its potable water-purification plant — already the world’s largest — to recycle 130 million gallons of effluent daily. The Metropolitan Water District of Southern California is eyeing a new $3.4 billion recycling facility that would secure a renewable source of drinking water for 19 million customers in the Los Angeles area.

For smaller communities or those with limited resources, however, a more modest approach can be just as effective, says Anne Thebo, senior researcher at the Pacific Institute, a nonprofit water conservation think tank in Oakland, California.

“The local context can really give communities flexibility in developing their water-reuse plans,” she notes. Agricultural communities hold an advantage here, she says, because many forms of irrigation don’t require recycled water that’s clean enough to drink. But all communities have some flexibility in their ability to use treated effluent, because water used to irrigate timber or lawns can be lower in quality than that used for pasture grass like alfalfa or crops that can be eaten raw, such as strawberries and lettuce. Developing a water-recycling plan that suits the needs of the community can diversify a region’s water portfolio and offset overall demand.

Read the full article about wastewater recycling by Naoki Nitta at Grist.