TULSA, Oklahoma - Some City of Tulsa water customers are getting unexpected bills for water they didn't know they were using.

A delay in city billing coupled with routine meter problems is leading to bills in the hundreds of dollars.

We started hearing from customers getting the bills and wanted to know why it was happening.

Turns out, someone at city hall figured out there was a backlog of the bills, so a big bunch of them went out at once.

A little water meter created a big bill for the owner of an east Tulsa house. Brandy Trout opened her mail and found a water bill for $800.

"They told me if I didn't pay, I would be getting cut off notices," she said.

Trout got an explanation with the bill that said her meter wasn't working for a year and a half.

Once the city noticed it, the meter was replaced and an estimate was made of how much water she must have used.

That's what led to the big bill.

"The meter man comes out to do his job, the billing department should do their job, and now it all falls on me and I don't think that's fair,” Trout said.

Tulsa's utility billing department sends out late notices every day to customers who had already paid the amount they were billed.

Director Mark Weathers said five or six each day are for more than $500, but most are less, some in favor of the customer.

"There's probably a couple of hundred pending cases right now," he said.

Weathers said more customers are getting overdue notices now because of a new effort to catch up on billing mistakes.

“We had a backlog of that because of staffing and some procedural things which we've tried to correct,” he said.

Customers who get big bills can make payments over time, or appeal the estimate they've been given.

Trout said it's going to be hard for her to make up the $755 in back payments, on top of the regular payment, even if it's over time.

"If they mess up they want you to pay for their mistakes and I don't think that's fair," Trout said.

Trout plans to appeal the amount, but the city has also given her the option to pay it out over 15 months, the amount of time the meter wasn't working.