California allows wastewater to be recycled into drinking water
California officials voted Tuesday to allow wastewater from showers and toilets to be treated into drinking water as the state braces for years of drought-related shortages.
The rules, adopted by the State Water Resources Control Board, made California the second state, after Colorado, to allow agencies to tap into a water source that residents have largely washed away for generations. Officials in San Diego, Los Angeles and Santa Clara are already preparing to build water treatment systems that could provide drinking water to hundreds of thousands of homes.
Many areas in the parched West already use treated wastewater for outdoor irrigation or to recharge underground aquifers, where the water is further cleaned as it percolates through the ground. But the idea of sending treated wastewater directly to homes has long struggled to overcome a nuisance factor in California. Opponents first denounced the process as a “toilet drain” in the 1990s, when proposals emerged in the Los Angeles suburbs.
But in the decades since, advances in water purification technology have been made while public opposition has weakened as climate change has strained and disrupted water supplies in California, the nation’s most populous state.
“This is an exciting development in the state’s ongoing efforts to find innovative solutions to the challenges of extreme weather caused by climate change,” said E. Joaquin Esquivel, chairman of the Water Resources Board. He added that “these regulations ensure that the water produced is not only safe, but purer than many drinking water sources we now depend on.”
More than 39 million people live in California, and the demand for water to support them – and the nation’s largest agricultural industry – has shaped the state’s history. Although intense winter storms saturated much of the state last year, California suffered an extreme drought that scientists say spanned the driest three-year period on record. The drive to exploit every drop in the state’s aquifers, rivers and reservoirs has only escalated under the pressure of climate change.
Water regulators spent more than a decade developing the rules for wastewater recycling, but they faced a Dec. 31 deadline under a state legislative mandate. The vote, which was unanimous, followed years of evaluation, including a review by a dozen outside scientists and engineers.
The newly authorized system will allow recycled wastewater to be brought up to drinking levels within hours and pumped directly back into pipes that supply drinking water to homes, schools and businesses, state officials said. The new rules will not require water agencies to immediately start using drinking water, but will allow those willing to invest in the necessary infrastructure to submit plans for state approval after regulations are finalized next year.
Mr. Esquivel noted Tuesday that residents living downstream from larger cities already rely on some of the water that has been treated and returned to the rivers. And Felicia Marcus, a longtime California water policy expert and Mr. Esquivel’s predecessor as board chair, noted that water-scarce places, such as in Africa and on the International Space Station, already recycle their wastewater. She called the vote a “historic milestone for climate resilience.”
“Right now, we are sending rivers of highly treated wastewater to the ocean at a time when both our Colorado River supplies and our Sierra supplies are likely to be subject to more frequent and drier droughts,” she said.
Ms. Marcus said two water recycling projects in Southern California will be among the largest in the world when completed. One effort in Los Angeles could supply up to 30 percent of the city’s water, she said.
“Today’s milestone approval is a real breakthrough,” said Sean Bothwell, executive director of the California Coastkeeper Alliance. “It’s time to stop the practice of using water once and then throwing it away.”