"It can amount to a lot of money that people don't have," said Shelton, explaining the reason for her grassroots campaign. "It looks like a lot of people haven't filed."
About 25 percent of city homeowners who received the homestead credit in the most recent tax year have not applied, Young estimates.
At most, there are 1.47 million owner-occupied homes statewide that are eligible for the homestead credit, he said. As of mid-December, about 940,000 applications have come in from across the state.
As assessments decrease, the value of the credit declines, too. Since property assessments dropped the past few years, only 482,000 property owners are expected to see any financial benefit next year — far fewer than in the past, he said.
Still, Young estimated about 125,000 homeowners might miss out on some benefit if they don't apply.
The online database that records processed applications has been an assurance to homeowners who applied some time ago, but those who applied in recent weeks cannot expect the database to be updated with their information before the Dec. 31 deadline, Young said.
It will be many months into the new year before all of the applications have been reviewed and the database reflects those submissions, he said.
Others have taken on outreach programs similar to Shelton's. Maria Wolf, a real estate agent who lives in Olney, has been checking the tax department's online database with her clients' and neighbors' addresses and getting in touch with them if it shows a homestead application has not been processed for their property.
"It's staggering how many people have not done it. It's a big chunk of money," Wolf said.
Some homeowners have experienced problems with the process, such as delays after requesting a confidential access code that is required to apply online. The unique codes were sent out by mail to homeowners in their assessment notices, but many people threw away or misplaced them, and now need their codes re-sent.
The code, intended to protect homeowners from false applications being submitted on their behalf, is not required on the paper version of the application, which requires a signature to guard against fraud.
Annapolis homeowner Brad Pitt requested an access code from the state at the beginning of November. It took weeks to receive it, he said, and when it arrived it wasn't recognized by the Web application form. Eventually, he opted to mail in a paper application.
"If I am having this much trouble, I cannot imagine my parents getting through this process," Pitt said.
The delays in responding to code requests, processing applications and responding to emails reflects a lack of staff, Young said. Eight people work on homestead credit issues in the tax department's headquarters, he said.
During October and November, the homestead team was answering 200 calls an hour and receiving hundreds of email requests each day, Young said. They're overwhelmed, he said.
"They don't have the staff they really need for the final push," said City Councilwoman Mary Pat Clarke, who also has been encouraging people to register before the deadline. "They're doing the best they can."
Although there is still time to get an application in, at least one legislator is concerned not enough people will hear about it by the end of the month.
State Sen. Joan Carter Conway plans to introduce legislation in January to extend the homestead credit application deadline until June 1, 2013.
"I have already drafted the legislation," Conway said. She plans to bring it up at the beginning of the General Assembly session, which begins Jan. 9.
Extending the deadline would create complications for the tax department, Young said. Because of the timing of the tax billing system, counties would have to issue some revised tax bills in fall 2013, he said. That's confusing for taxpayers and will cost more for the counties, he said.