INDIANAPOLIS -- Many Marion County homeowners are getting bigger property tax bills than they should because a computer did not apply a deduction.

Residents should check their exemptions to ensure that all of the possible credits they should have are there, 6News' Norman Cox reported.

Kelli McNamara said she was prepared for a large increase in her home's property tax when the bill arrived, but she was shocked at what she saw. The bill jumped from about $1,800 last year to almost $5,000 this year.

McNamara's husband, Gavin, is an accountant. He quickly saw that their house's homestead exemption, worth thousands of dollars, had vanished from the bill.

"So, I went to the county assessor's office, and I'm not sure how I started my sentence, but he was able to finish it for me," McNamara said.

Many homeowners in the same area had the same problem. The issue particularly affected people who had bought houses and filed for homestead exemptions in 2005.

"He said it was a computer glitch of some sort," McNamara said.

Keeping track of the homestead exemption is the responsibility of the Marion County Auditor, but the Washington Township Assessor's Office is getting an earful about the problem.

"We've run into quite a few people that have had that happen," said Joline Ohmart, Washington Township assessor. "For some reason or another, those did not get applied."

Residents who live in their home and pay a mortgage should have at least two codes under the exemption section of their bill.

One is for a mortgage deduction and the other is for the homestead deduction, the more valuable of the two.

McNamara said fixing the problem was easy once it was found.

"They knew the problem immediately. They were able to just fix it on the computer, and they said I would get a revised bill in a week-and-a-half to two weeks," McNamara said.

The auditor's office did not provide 6News an explanation as to how the problem happened, but fixing it save the McNamaras a lot of money. Restoring the homestead exemption reduced their bill by $1,800.