It’s not everyday that you receive an electric bill for more than $100,000.

Fortunately for Denise Mehal, business manager for the Coupeville School District, the bill didn’t come as a complete surprise.

The school year might be ending this week in Coupeville, but it will still be a few months until the school district gets caught up paying about $103,000 it owes Puget Sound Energy for roughly eight months of electricity usage.

Puget Sound Energy and the Coupeville School District have agreed to a three-month installment plan to pay off the debt that PSE admits was caused by “human error” on its part when a usage meter to the high school and middle school was inadvertently removed from the company’s billing system, said Akiko Oda, PSE’s media engagement program manager.

That mistake occurred in August. Yet it wasn’t until seven months later — in March — that PSE discovered the error, notified the Coupeville schools what had happened and shed light on the astoundingly outstanding balance.

Mehal detected that something was fishy over the winter when bills from PSE started coming in lower than normal and she notified the company in January, setting off an investigation.

“At one point, we even had a credit,” Mehal said. “That really threw up the red flag.”

Part of Mehal’s job with the district is to track bills, which she said can be tricky when it comes to electricity since there are eight meters that serve the entire district.

Bills are broken down by meters for different buildings and bills don’t always reflect each meter every month.

“That’s why sometimes we have to wait and see,” Mehal said. “We are thinking, ‘Maybe they’re just catching up.’”

But it became obvious that something was askew. The Coupeville School District pays about $350,000 a year to heat, light, circulate air and power various equipment and electronic devices, Mehal said.

The error was traced to Aug. 19, 2014, when Puget Sound Energy came to Coupeville High School and Middle School to remove a temporary test meter that the school district requested a month earlier to verify the operation and accuracy of the existing meter, Oda said.

When the temporary meter was removed, a PSE employee accidentally removed the usage meter from the company’s billing system, meaning that energy usage for the middle and high schools failed to get recorded.

That set in motion a series of bills that fluctuated strangely and raised eye brows along the way.

“Due to what happened, we are looking into improving our processes and training to ensure the necessary steps are taken for re-activating accounts following tests conducted in the field,” Oda said. “We have practices in place to catch accounts that show no energy usage. We are grateful for the Coupeville School District’s patience and understanding as we work to address this issue.”

Mehal said the experience has taught her to look at all bills a little more carefully.

“I think it was an honest mistake by PSE that they are working hard to correct,” said Coupeville Superintendent Jim Shank. “PSE has been a great partner in the past and we look forward to our future working together.”