Rolesville, N.C. — Abandoned quarries in Wake County contain billions of gallons of water that at least one official said should be tapped to augment the supply of available drinking water.

Some of the former mining pits are filled by aquifers, while others are fed by diverted streams. They usually contain more than 1 billion gallons each. By comparison, Falls Lake contains close to 15 billion gallons when full.

"We've seen them up to 4 billion gallons," said Tommy Esqueda, director of Wake County Environmental Services. "The smallest I've seen is about 1 billion gallons."

The county has no long-term plans for tapping quarries, but Esqueda said he would like to change that. The county could begin studying possibilities later this year, he said.

"There is capacity and volume there. So, (the question is) how can we develop it?" he said.

Durham tapped into Teer Quarry at the northern edge of the city in January, when its two reservoirs had about a month's worth of quality drinking water left between them. The city recently stopped pumping water from the quarry after rains helped replenish the reservoirs.

Harnett and Orange counties also have long-term plans to use quarries for drinking water.

Doy Sherrill, who owns a former granite quarry near Rolesville, said he would gladly sell some of his water to Wake County.

The 54-acre quarry, which is filled to a depth of 82 feet in places, contains enough water to supply most of Rolesville's needs. Sherrill said the county expressed an interest in buying the quarry several years ago, but he now leases it out to scuba divers.

"It's enough water that they could use some of it. It'd be good if they did," he said.