When a California resident began to question the price of his electricity bill every month, he realized an up to 18-year-old mistake was costing him well over his personal usage.
Ken Wilson, a Pacific Gas and Electric (PG&E) customer who has lived alone in an apartment complex in Vacaville since 2006, told ABC News' San Francisco station he started to notice his bill rise a few months ago.
In an effort to lower costs, Wilson told the outlet he tried to cut back on usage and purchased a device to help monitor how many watts his appliances use.
"Even after I turned off my breakers, I kept going outside to check my meter to see if it was still running and it was still running," Wilson told ABC7.
"I couldn't believe it," he added.
Wilson said he contacted PG&E about the issue and they sent a representative to his apartment to check his meter, who confirmed his suspicions were not unfounded.
The utility company released a statement to ABC News saying Wilson had been paying the electricity bill for the apartment next to him "since potentially 2009," three years after he had moved in.
"Our preliminary investigation has found the meter number for the customer's apartment was being billed to another apartment since potentially 2009," a spokesperson for PG&E said.
PG&E owned up to the mistake and maintained the company is "committed to rectifying the situation with the customer," the statement said.
Since he's had the same agreement with PG&E since he moved into the complex in 2006, Wilson told ABC7 and other media outlets he believes the costly mistake has been going on longer.
"We sincerely apologize for the oversight and regret any inconvenience caused by the duration of this issue," the spokesperson added.
In an update to ABC News, the PG&E spokesperson said Wilson's meter was fixed so that he would only be paying his share of electric usage and that he was credited over $600 to his account with the company.
PG&E also urged fellow customers who are worried about their usage and billing to verify their meter is correct by comparing the meter ID number on the electric panel to that on their monthly bill.