Recycled water catches on — outside of Sacramento
New state rules adopted last month allow purified water to be sent right from sewage treatment plants to drinking water reservoirs, but Sacramento area residents shouldn’t expect to be swimming in or drinking water that recently swirled through local sewers any time soon.
Though the Sacramento area traditionally has among the highest per capita water use in California, there has been little interest among local water districts in using recycled water to augment local drinking water supplies. The reason? Local waterways such as the Sacramento and American rivers and Folsom Lake provide abundant and comparatively cheap water supplies. The sorts of major infrastructure investments that would make recycled drinking water a reality would cost more than the water to which local providers have access. Officials say they can afford to hold off for now.
That’s not to say recycled water won’t ever run from Sacramentoarea residents’ taps, but local water officials say that prospect is still decades away.
“At some point the consequences of climate change — the changing patterns of precipitation, the increasing volatility of water supplies through California — might drive us towards those types of investments,” said Paul Helliker, the general manager of the San Juan Water District in Granite Bay.
Added John Woodling, executive director of the Sacramento Regional Water Authority: “We’ll certainly have more time to think about how that happens with recycled water going forward.”
Southern California doesn’t have the luxury of waiting. Districts in San Diego County are quickly moving forward with reservoir augmentation plans under the rules passed in March by the State Water Resources Control Board.
Millions of Southern Californians also already are drinking and showering with water recycled from sewage treatment plants and rerouted through local groundwater basins.
The recycled water, which is treated first through a process known as reverse osmosis to render it safe to drink, is either pumped directly into an aquifer or allowed to flow into ponds sitting on sandy soil. From there, the water seeps into the groundwater supply.
As is the case under the new reservoir augmentation rules, the water has to be treated again before it’s sent into municipal drinking water lines.
Officials at the Water Replenishment District of Southern California use recycled water to augment the two vast groundwater basins that provide drinking water for 4 million people in 43 cities in Southern Los Angeles County.
Each year, the agency sends about 100,000 acre feet of recycled water into recharge ponds that fill the district’s two intensively managed groundwater basins. An acre foot is 326,000 gallons.
The agency decided about 12 years ago that it needed to wean itself off water pumped in from Northern California and the Colorado River because the supplies were becoming so unreliable and expensive.
Thanks to local stormwater capture and the recent addition of recycled water, the agency is a year away from being entirely independent from imported water, said Robb Whitaker, the district’s general manager.
An added perk: the locally sourced water costs two thirds as much as buying imported surface water.
“Quite frankly, it’s a waste to not use water as many times as we can,” Whittaker said.
Recycled water’s appeal has been growing in drought-prone California because it provides a reliable local source to replace water pumped or piped in from faraway rivers and streams. Those imported supplies are becoming less reliable and more expensive amid droughts and climate change, said David Sedlak, a professor of environmental engineering at UC Berkeley who has studied recycled water.
“The thing about potable water recycling is it’s more or less a drought-proof supply,” Sedlak said. “People are going to use about the same amount of water in their homes for showering, and washing dishes and flushing, and so that water is going to be there even in the dry years.”
Sedlak said Californians also are becoming much more accepting of recycled water, when just a couple of decades ago the notion of “toilet to tap” might have had them turning up their noses.
Helping speed things along: The five-year drought that ended last year that had Californians letting their lawns turn brown and placing buckets in their showers. California lawmakers also passed legislation in 2010 and in 2013 that seeks to make recycled water a reality. Recycled water also is a key component of Gov. Jerry Brown’s Water Action Plan first signed in 2014 during the worst of the drought.
The Sacramento area hasn’t completely rejected the idea of recycled water, it just hasn’t yet used it for drinking.
A few sewer treatment plants supply recycled wastewater to local costumers, but the water can only be used for irrigation or industrial use. The recycled water flows through purple pipes that are on closed systems, separate from the drinkingwater lines.
El Dorado Irrigation District has a purple pipe program, so does the Sacramento Regional County Sanitation District’s water reclamation facility, which sends up to five million gallons per day of recycled water through its purple pipes to customers in the south county.