FOUNTAIN VALLEY  (AP) — An Orange County water district said Friday it is adding more purified wastewater to its groundwater basin, helping to continue its reliance on mostly local water sources during the drought.

The Orange County Water District expanded its groundwater replenishment system to produce 100 million gallons of water a day, up from 70 million when it began in 2008.

The system purifies treated wastewater and releases it into the groundwater basin where it is pumped out as drinking water for residents in the central and northern parts of the county.

“It’s a great day for all people that drink water,” said Tom Beamish, chair of the Orange County Sanitation District, adding that more than half of his district’s wastewater is now being reused. “We are a model for the rest of the state.”

The $142 million expansion began three years ago, with the additional water coming as California grapples with its fourth year of drought.

Earlier this year, the state mandated cutbacks by local water agencies, and residents have been trying to conserve by tearing out lawns and taking shorter showers.

Earlier this month, the city of Riverside sued the state water board over the restrictions, claiming the rules are unfair because the city has ample groundwater supplies.

In the Orange County district, about two-thirds of the water comes from the groundwater basin and a third is imported from Northern California.

With the expansion, the replenishment system now produces enough water for about a third of the district’s 2.4 million residents. The district hopes to further expand the project to produce 130 million gallons of water each day.

When the project began, the district had to overcome public skepticism about introducing wastewater — after it was treated and purified — into the system that delivers drinking water to residents.