"There will probably not be a time when we are perfect," Eskelsen said. "But we are always trying to do better."

Several energy managers say they work daily with utility companies, and report good relationships. Districts will sometimes catch an error before a bill is paid and notify the utility. Though not technically recovered money, those catches are tallied as such because money not actually owed would have been spent had the error not been found. Jordan's Devey has Questar on speed dial, and his custodians record their own meter readings to compare with power bills.

Sometimes, things don't add up.

Most errors, school officials say, are inadvertent human errors including computer input mistakes.

One Weber school has collected years' worth of refunds for a $4.50 a month charge for garbage collection it never received, Hales said.

Davis District has recovered about $6,000 in overcharges discovered when East Layton Elementary's power bill didn't drop despite a power upgrade, utility services director Paul Barnes said.

Cache School District was overcharged $4,000 on a municipal power bill due to a misplaced decimal, district energy manager Kendall Allen said. He caught the error before payment was made.

"They (district bill payers) might have caught it, they might not have. But my guess is they would have paid it and not questioned it," Allen said. "Taxpayers could have been out that money."

Such errors appear obvious.

Others are hidden in estimates.

Utilities can estimate charges based on a customer's history of use. Sometimes they have to because weather conditions or watchdogs in back yards prevent a reading. But they're still supposed to read meters at least once in a two-month period, said Orchard of the Public Service Commission.

And for the most part, they do, Questar spokesman Darren Shepherd said.

"To assure our customers, residential and commercial, we go to great lengths to ensure the accuracy of their billing," Shepherd said. "Although we make an effort to get out to every meter and read it every month . . . when you miss it one month, it doesn't mean someone's being overcharged. It can always be trued up on the next meter read."

Not always.

Weber energy managers found Questar incorrectly estimated a Weber High School meter had turned over, kind of like an odometer would at the millionth mile, resulting in unnecessarily heavy bills. Questar in late July was calculating the size of the refund.