California's Water Resources Control Board recently approved new regulations in a unanimous (一致同意的) vote—toilet or shower wastewater will be recycled and pumped into the public drinking water system.

In 2023, more than 97% of California has been in moderate to severe drought, while water suppliers are struggling to keep up. A 2022 water supply and demand report indicated that around 18% of water suppliers were at risk of facing potential shortages. "The reality is that anyone out there on Mississippi River and on Colorado River, and anyone out there taking drinking water downstream is already drinking ‘toilet to tap'," said Esquivel, a director of the Board.

Early in the 1990s, the state was struggling to overcome the distaste its residents had toward drinking recycled water. Their efforts fizzled out when the phrase "toilet to tap" caught on and met with fierce resistance. The idea became too unpopular to be implemented. Despite the negative name, the regulations are the key to ensuring the supply of drinking water.

California's new regulations would let water agencies to treat wastewater, and then put it back into the drinking water system. It has taken officials more than 10 years to develop these regulations, a process that included several studies by independent groups of scientists. To put the scheme into effect and build huge water recycling plants, however, water agencies say they will need to prove to people that recycled water is not only safe to drink but also under monitoring.

The new regulations require the wastewater be treated for all bacteria and viruses. In fact, the treatment is so intense that it removes all of the minerals that make fresh drinking water taste good. That means the minerals need to be added back at the end of the process. "What we have here are standards, science, and importantly monitoring that allow us to have safe pure water, and probably better in many instances," said Esquivel. He added that it takes time and money to build these treatment centers. So, they will only be available for bigger cities at first.