The State Water Resources Control Board, in a unanimous vote Tuesday, outlined for the first time how water suppliers can treat recycled water and send it directly to taps. Currently recycled water is mixed into aquifers or used for irrigation and other non-drinking purposes.
鈥� which have been more than a decade in the making and were 鈥� aimed at ensuring that germs and chemicals are scrubbed from treated sewage.
Often dubbed 鈥渢oilet-to-tap,鈥� the process is actually much more extensive and complex, requiring multiple treatment steps . The new rules also call for extensive monitoring to ensure the treatment is working.
Between flush and faucet
The sewage will be bubbled with ozone, chewed by bacteria, filtered through activated carbon, pushed at high pressures through reverse osmosis membranes multiple times, cleansed with an oxidizer like hydrogen peroxide and beamed with high-intensity UV light. Valuable minerals, such as calcium, that were filtered out will be restored. And then, finally, the wastewater will be subjected to the regular treatment that all drinking water .
California will be following Colorado, , and Texas, where the nation鈥檚 first direct potable reuse plant was built a decade ago. Rules are in development in and , as well.
Nothing will go into effect immediately; the regulations must undergo a final review by the Office of Administrative Law before being implemented, likely next summer or fall. The first facilities are several years away.
鈥淎 city produces wastewater during a drought, and having that source available to augment other (drinking water) supplies can be critical,鈥� said Darrin Polhemus, deputy director of the state water board鈥檚 Division of Drinking Water.
The water is expected to be more expensive than imported water, but also provide a more renewable and reliable supply for California as climate change continues.
The expense of the treatment and monitoring means that it will likely be limited to large urban water providers, Polhemus said.
鈥淚t will offer a resilient source in drought times for large water systems to be part of their portfolio. It鈥檚 not going to be a singular water source for some small community on the coast 鈥� that鈥檚 just not going to work out well the way these regs are written,鈥� Polhemus said.
Fewer than a dozen people commented about the regulations at today鈥檚 meeting, all in support.
These regulations 鈥渞eally herald a new era for water reuse in California,鈥� said Jennifer West, managing director of the trade association WateReuse California. 鈥淐ommunities across California will be able to benefit from this new, safe, resilient supply.鈥�
Some environmental groups urged the board to adopt deadlines for more aggressive monitoring to reassure consumers about safety and ensure no outbreaks or other health scares derail the projects.
Board Chair E. Joaquin Esquivel directed the staff to report back within the next year to update the board on monitoring, contaminants and other issues.
A panel of independent experts determined that the regulations 鈥渁dequately protect public health,鈥� but reported that some requirements, such as for removing disease-causing germs, , driving up costs.
This could 鈥減ush utilities toward less environmentally desirable alternatives, such as extracting groundwater without replenishing it,鈥� the panel said in a memo to the state board in September. It could also 鈥渓imit the ability of smaller communities to use鈥� the recycled water as drinking water.
鈥淚 don鈥檛 think anyone should be surprised that a water board regulator would choose to err on the side of public health,鈥� said Kevin Hardy, executive director of the National Water Research Institute, a non-profit that coordinated the expert panel.
The Metropolitan Water District, the giant agency that imports water to Southern California, is already on its way to being among the first to directly use recycled water for drinking supplies with , a multi-billion dollar project with the Los Angeles County Sanitation Districts.
By 2032, the plant is expected to produce about 115 million gallons of recycled water a day, enough for 385,000 Southern California households. Most will replenish groundwater, but some is expected to be added to drinking supplies upstream of Metropolitan鈥檚 treatment plant for imported water.
Mickey Chaudhuri, interim chief of operations at Metropolitan, applauded what he called a historic milestone.
鈥淭his marks a pivotal moment in California鈥檚 water management history,鈥� he said at the public hearing today.
Last year, Gov. Gavin Newsom called for increasing recycled water use in California and more than doubling it by 2040.
Most treated sewage 鈥� alone 鈥� is released into rivers, streams and the deep ocean.
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