LOS ANGELES (NewsNation) — California regulators Tuesday approved new rules to let water agencies recycle wastewater and return it to the pipes that carry drinking water to homes, schools and businesses.

The state has struggled for decades to secure reliable sources of drinking water for its nearly 40 million residents. The move signals a shift in public opinion on a subject that as recently as two decades ago prompted backlash that scuttled similar projects.

California has been using recycled wastewater for decades, but it hasn’t been used directly for drinking water. Orange County operates a large water purification system that recycles wastewater and then uses it to refill underground aquifers. The water mingles with the groundwater for months before being pumped up and used for drinking water.

California’s new rules would let — but not require — water agencies take wastewater, treat it, and then put it right back into the drinking water system. California would be just the second state to allow this, following Colorado.

Michael McNutt of the Las Virgenese Municipal Water District said the process, known as “direct potable reuse,” has already been used by Australia and Singapore for years.

“What direct potable reuse will do is further treat that water using proven technology and put it directly back into the drinking water system,” he said. “It’ll go back to your home; this water will have been treated at least six or seven different times before it goes back into your home to use. It’s very safe.”

McNutt said water treated by direct potable reuse is often treated to levels above that of drinking water standards.

“That’s one of the things that (people) across the country need to understand: Public health has always been the top priority of this. The State Water Resources Control Board (in California) has been studying this intensively for 13 years. The state of Colorado has already allowed this process.”