ATLANTA -- The city of Atlanta lost more than 10 billion gallons in 2015, according to an audit obtained by 11Alive News.

While Atlanta’s Watershed Management says aging infrastructure is to blame, the 11Alive Investigators uncovered some residents say the city shares some responsibility by not repairing leaks for months at a time.

John Ballard is one of those residents.

The Piedmont Heights homeowner says he and his neighbors have walked past a leak at the corner of Monroe and Piedmont Way for nearly three months. They reported to the city multiple times.

”Things don’t get done very fast around here,” Ballard said. “That’s gallons of water coming out a minute.”

Lillian Govus is the director of communications with Atlanta’s Watershed Management. She says the city responds to emergency water issues first, which can create delays when repairing smaller leaks.

“Over the weekend, we had more than five water main breaks,” said Govus.

According to water audits, Atlanta lost about 9.7 billion gallons each year in 2013 and 2014. It jumped to more than 10 billion gallons in 2015. That’s about $326 million of wasted water.

To put that water loss in perspective, that’s enough water to fill up every water tank at the Georgia aquarium 1,000 times.

“What we have here is a very aged infrastructure,” Govus said.

“That tunnel we’re building to the Chattahoochee replaces a water main that was put in the 1890s," she said. "Shortly after Thomas Edison had that great idea with the light bulb, we put in that line and we’re still using it.”

Aging infrastructure isn’t always problem. It’s human error, too, in other municipalities.

In DeKalb County, its water department reported losing nearly 4 billion gallons of water in 2015.

According to an audit, “meters into [its] distribution system are installed incorrectly and therefore not guaranteed to be accurate.”

It failed the audit with a 61 out of 100.

Burk Brennan is the DeKalb County press secretary.

“We’ve had a little bit of a leadership change in the watershed department. We’ve been re-evaluating all of our processes, reevaluating all of our reporting,” said Brennan.

Water conservation organizations, like the Georgia River Network, say the water loss and failing audit are concerning.

“If that is indeed the case, there are a lot of questions as to why that would happen," said Georgia River Network water policy analyst Chris Manganiello. "They’ve been doing these audits already for three or four years. So, why in the fifth year would we see this decline?”

The city of Atlanta and DeKalb County are both implementing large capital improvement projects they believe will reduce water loss in the next few years.

Atlanta is spending about a billion dollars on infrastructure upgrades and will it take about 5 years to complete.

.Click here for how to report a leak in Atlanta.