That year, errors were found on 2.7 percent of 7,508 invoices, the utility reported. It overbilled by $56,584, and underbilled by $35,968.

In 2003, Utah Power reports a 1.6 percent error rate, with $50,870 overbillings, and $17,955 underbillings.

But so far this year, the utility has a 9.4 percent error rate — mostly favoring school districts. It overbilled districts by $10,523, but underbilled them by $49,905, mainly because it misassigned a seasonal rate code, Eskelsen said. The utility found the error and adjusted bills the following month.

In a separate case, Murray School District found it was not paying enough for municipal power, said Rodney Pace, district buildings and grounds supervisor and energy manager.

"We had to pay them back."

Still, say other districts, money is out there waiting to be had.

Granite District's McLeod keeps memorabilia of more than $100,000 in utility reimbursements: copies of a $62,491.60 check from Granger Hunter Improvement District (see graphic below); $27,687 and $22,189 from Utah Power, and others.

They're his trophies.

"(They) give me incentive to go after more. This really is the funnest job in the district."

But it can be a big headache, too.

McLeod has been installing capacitors in order to get rid of Utah Power's inefficiency, or "power factor" penalties on his schools.

But at Granite High the efficiency efforts didn't work, until he discovered, in the school's deepest tunnels, additional transformers that weren't even on utility maps.

McLeod got the power factor problem taken care of.

But he inherited a new one.

Utah Power claims the district owns the transformer and will be responsible for its upkeep.

But if that's the case, the district for 15 years should have been getting a voltage discount, McLeod said.

The utility offered $5,000 for two years' worth of the discount, under the basic statute of limitations regulators put on recovery, McLeod said. However, he plans to fight for all $38,000 in overcharges. He may call the Attorney General's Office for legal guidance.

"To me it's unfair a utility company doesn't give us the voltage discount if in fact they've known that they're ours . . . but not said anything," he said. "But I haven't given up yet. It's a matter now of arm wrestling and letter writing and trying to recover as much of that as we can."

Eskelsen of Utah Power says the company has been working closely with Granite to make sure things are set right. It even is sifting through all Granite District billing to ensure accuracy.