COSTA MESA (CBSLA.com) — Despite California’s escalating drought, one local city isn’t having to rely on outside sources for its water supply.

That’s because Costa Mesa has a massive reservoir that sits 1,000-feet beneath the city and supplies the needs of 108,000 consumers, including John Wayne Airport.

“They spent about $22 million to build this facility and to pull that water up and treat it and provide that high level of confidence to our consumers to give us that 100 percent local reliability,” Phil Lauri of the Mesa Water District, said,

The presence of the ancient aquifer and one other allow the city to be completely self-sufficient not relying on precious, water sources.

The water pulled from the ancient reservoir is enough to supply 30,000 customers each day.

Once the water is pulled from the well, it is purified. It’s then offered to customers at a price that’s substantially less.

“Imported water is about $1,000 in acre-foot. This water is about $300 in acre-foot,” Shawn Dewane of the Mesa Water District said. “So if we had to buy water from the imported supply, we’re paying about $700 more per acre-foot so this stabilizes the cost to our community and actually reduces it.”

The reservoir known as the O.C. Groundwater Basin was tapped into by engineers in 2013.