Property owners could be able to apply for most city tax credits through an online system by the end of the year, a set-up designed to improve the accuracy of a process that has been troubled by errors, officials said Friday.

The online system went live Friday for developers of large apartment buildings, said William Voorhees, the city's director of revenue and tax analysis. He said he expects it to open to applications for the historic properties tax credit this summer and most others by the end of the year.

Once submitted, applications will go to departments for review. The finance department provides a final sign-off.

Officials said the online system will enhance accuracy by allowing automatic computation of the credit. The system, which was developed in-house, creates an "audit trail" and blocks applications if it detects submission errors.

"It eliminates a whole host of issues that can occur," Voorhees said, adding that it has taken more than a year to develop and will eventually serve thousands of users.

A 2012 investigation by The Baltimore Sun showed that the city did not collect more than $1.5 million from commercial property owners because of calculation errors in the historic tax credit program. Last July, about 315 property owners saw significant increases in their property tax bills after miscalculations were discovered that provided more generous breaks than was accurate. Bills for other affected properties were under review.

"We looked at the errors we found, we've looked at the processes we go through, and we decided what we needed was to re-engineer the whole process," Voorhees said. "We want to be sure that we have all the i's dotted and t's crossed."

The goal is to have everyone use the online system, but accommodations will be made for people who do not have access to a computer, he said.

nsherman@baltsun.com