Lawrence city commissioners still are interested in a November election to fund a new police headquarters building, although new questions have arisen over the project’s $30 million price tag and the possible tax increases to fund it.

City commissioners on Tuesday were presented with a new funding scenario that includes both a 0.2 percent sales tax for 20 years and 3.7 mills of property taxes to pay for the project. That funding scenario is significantly larger than past projections because it includes funding not only for the building but also for 20 years worth of funding to grow the size of the police force.

“The need for additional equipment and policing is still very much there,” said Police Chief Tarik Khatib, noting the department recently has cut school resource officers and traffic officers in order to increase the size of the city’s patrol force.

Some commissioners, though, already were balking at the size of the potential tax increase. Both Mayor Mike Amyx and Commissioner Bob Schumm said they want to focus on finding funding for the building. Both said they prefer to let future commissions decide on a year-by-year basis what increases may be needed for additional police personnel.

A 0.2 percent increase in the city’s sales tax would raise the rate to 8.9 percent. An additional 3.7 mills of property taxes would add about $64 a year in taxes to a $150,000 home.

Commissioners also reviewed about 10 other less aggressive tax scenarios that would provide funding only for the construction of the building, but not any additional police officers. They included:

• A 0.3 percent sales tax that would sunset after 10 years.

• A 1 percent sales tax that would expire after 2 years, plus 1.3 mills of property taxes that would continue indefinitely.

• A 2.8 mill property tax increase that would allow the project to be funded without a sales tax increase.

Commissioners made no decision on a potential tax increase, and also did not yet place the issue on the November citywide ballot.

First commissioners must decide how much the new police headquarters building should cost. Commissioners were told by architects that they’re planning for a 103,000-square-foot building that would cost about $30 million to construct.

Some commissioners expressed concern at that price, but representatives with Lawrence-based Treanor Architects said that is below the national average for new police facilities, which currently are running about $250 per square foot to build.

“We don’t take the approach that this needs to be a Cadillac of a building,” said James Estes of Wilson Estes Police Architects, who also is working on the design. “We take an approach that it needs to be functional, and shouldn’t become a maintenance nightmare for the city.”

But commissioners directed staff members to work on some potential cuts that could be considered by the commission in future days. Particularly, commissioners asked about plans for about a 70-space underground parking garage at the facility. The garage would be used for the department’s fleet vehicles, but commissioners said they wanted to explore an above-ground parking option in an effort to save money.

Commissioners are expected to discuss the police headquarters building again at their meeting next week.