Georgia’s water providers are being asked to solve the decades-old (and sometimes centuries-old) Mystery of the Disappearing Water.

It used to be called “unaccounted-for water”: water that flowed out of a city’s water treatment plant but wasn’t purchased.

Where did it go?

A lot of it probably leaked out of pipes, some of it wasn’t billed, some was used by cities themselves to water ball fields or test fire hydrants, and some might have been lost through inaccurate meters. The list goes on.

Many utilities have long considered it acceptable to lose an average of about 15 percent of treated water this way.

Most businesses would never let that much of their product dribble away without investigating. But water has historically been so cheap -- and plentiful -- that cities could afford not to pursue these losses.

However, with droughts becoming more frequent and Southeastern water wars intensifying, that luxury is gone. The Water Stewardship Act passed last year is requiring most water providers to audit their water losses, in many cases for the first time, and eventually create plans for reducing them.

The impact on water resources could be significant. Lebone Moeti, an environmental engineer with the Georgia Environmental Protection Division drinking water program, estimated that about 30 percent of municipal water could be draining away as “lost water.”

The largest water providers must complete their audits by March. Water systems serving between 3,300 and 10,000 customers have an additional year to finish theirs. All the audit results will be posted on the Georgia Environmental Protection Division website, Moeti said.

Reducing lost water not only helps reduce waste, it also saves cities money.

“Our main concern with it as a city is … if we pump water out of the ground and treat it, we want to make sure we’re getting paid for it,” said Monty Walters, utilities director for Warner Robins. “We don’t want to incur costs and not be getting a return on our investment.”

Walters said the city lost about 10 percent of its treated water in 2010.

“It’s something every city struggles with,” said Chad McMurrian, assistant project manager for ESG Operations in Perry, which contracts to handle the city’s water treatment and distribution system. “Or if they don’t, they’re not trying.”

ESG has leak detection devices spread around Perry, a work order system requiring quick responses to leaks, regular calibration of pressure gauges, and other steps to reduce lost water, McMurrian said. Even so, he estimated that Perry loses 10 to 20 percent of its water.

McMurrian said he hopes the new rules will create wider understanding of the problem and encourage public officials to invest in better equipment to find and prevent leaks.

The state is requiring water providers to use software developed by the American Water Works Association to calculate their annual water loss, divided by their “unavoidable” water loss. (Moeti explained that because all water systems are under pressure, any system will experience some leaks at pipe seams. But the amount considered reasonable varies with the size, pressure and the number of customers in each system.)

Each water provider must also report a “validity score” that indicates whether the data it used is specific enough to draw reliable conclusions. Many past estimates by cities weren’t made by closely analyzing data, Moeti said.

The software will also identify three areas that most need improvement in each water system. The water providers will likely be given six to nine months create plans for making cost-effective changes, although Moeti said there is not a specific time frame in the law for how quickly progress must be achieved.

1.6 billion gallons lost

The Macon Water Authority may be the only water system in Middle Georgia that has been using the software to do water audits for years.

“But we’ve never been confident about what it tells us or used it to improve our system,” said Executive Director Tony Rojas. This was partly because the amount of lost water seemed to swing wildly from one month to the next, probably because all meters can’t be read at the same time, Rojas said.

So the authority is paying contractor Cavanaugh & Associates about $100,000 to help the utility improve its data analysis and find ways to reduce water loss.

“What we want the state to know is we’re serious about it and we’re taking care of our business, so they know they don’t have to worry about the water authority,” Rojas said.

The contractor met with many authority employees Wednesday to report the results of its initial investigation.

Project manager Will Jernigan said the authority lost 1.6 billion gallons -- about 16.6 percent -- of the water it treated during the 12 months ending in June.

About 13 percent, or 1.3 billion gallons, was water that leaked away, with the rest being “apparent losses” that were actually caused by factors such as inaccurate water meters, he said.

Of the 16.6 percent of water lost, almost 6 percent is “unavoidable” loss and probably can’t be eliminated, Jernigan said.

Guy Boyle, the authority’s finance director, observed, “That shows the value our society puts on water. If that was natural gas or oil, a 6 percent loss would be unacceptable.”

The state-required method also puts a dollar value on the losses. But it values real water lost through leaks at a lower rate than “apparent losses” through accounting, billing and metering flaws.

Rojas questioned this, saying that they should probably both be valued at the higher level given Georgia’s water scarcity problems. Valuing them differently makes it appear less cost effective to repair leaks and conserve real water.

Rojas said that even from an economic standpoint, it might make sense to pursue the real water losses more aggressively because “we can show the state conservation on our side of the meter, without driving down customer consumption and revenue.”

Jernigan added that ignoring leaks creates long-term costs in the form of sinkholes and unnecessary water treatment plant expansions.

Dan Walker, utilities supervisor for Houston County, said its water system has not audited lost water since applying for a new water permit six years ago. At that time, about 10 to 15 percent of treated water was being lost.

Robbie Dunbar, Houston County’s director of operations, said the state’s new approach will force everyone to have specific improvement goals, which is good. But he pointed out that the deep aquifers south of the fall line know no political boundaries, so he thinks the state needs to also look at the issue regionally and not just city by city.

Keith Spillers, water supervisor for Fort Valley, said his system has never performed a water audit before, but 18 to 20 percent of its water may be lost before reaching customers.

“I think a lot of towns are going to have to have companies come in and check their whole system for leaks,” a move Spillers said he’s investigating for Fort Valley.

Smaller water systems have another year to complete their audits and can get extra help with the audits from the Georgia Environmental Finance Authority, Moeti said. The authority will also offer grants for leak detection efforts and low-interest loans to finance improvements, he said.

“Cost is an issue,” he said. “You reach a point of diminishing returns.” He could not say how the state would respond if a utility said it could not afford to make improvements.

“Our intent is not to be punitive but to get everybody to become good stewards of our water resources,” Moeti said.