The St. Mary's County commissioners gave unanimous approval Tuesday to a property tax credit for senior citizens.

Under the ordinance, which passed with the support of all five members of the Board of County Commissioners, county residents 70 or older who have a household taxable net income that does not exceed $80,000 will be able to effectively freeze their county property taxes at current levels. The move was intended to offset the rapidly rising property value assessments that make tax bills increasingly more difficult to afford for some seniors on fixed incomes.

"We truly do think this is needed," said Mary Ruth Horton, chairwoman of the St. Mary's County Commission on Aging, adding that the credit should help more seniors stay in their homes and "live a better quality of life."

The legislation has endured a protracted process. Last year, the county commissioners passed an ordinance authorizing the credit, but they had to wait to implement it until the General Assembly approved legislation authorizing the move. The legislature's approval included a provision that the credit would apply only to those of "limited income" -- a term left undefined -- and would sunset out of existence by 2008.

The county commissioners went back and forth over where to set the income limit and heard impassioned testimony from seniors at public hearings before settling on the $80,000 figure. County officials have said they expect this number makes only a small percentage of seniors ineligible for the credit.

Seniors can apply for the credit starting Monday, said County Treasurer Jannette P. Norris (D). If eligible they are eligible, their property taxes will be frozen at the previous year's level. The credit would offer a refund for the current tax bill, which must be paid by tomorrow.

"I think this is a good first step, and it will help a lot of seniors," said Pat Myers, the president of the St. Mary's chapter of the National Active and Retired Federal Employees Association. "The next thing we would like to do is have the sunset clause removed."

The tax credit could decrease county revenues by $163,800 in fiscal 2006 and more than three times that amount by fiscal 2008, according to estimates made before the limited income provision was inserted. The credit was not expected to affect county expenditures, and county finance director Elaine Kramer said she expects the revised ordinance will not have a significantly different fiscal impact.

"This was a long road, there were some difficulties along the way," said commissioners President Thomas F. McKay (R-At Large). He said he favors eventually removing the limited income test and the sunset clause, revisions that would have to come through the state legislature. "We have a little bit more work to do."