The Lawrence Police Department has a space problem — everything from lockers to interview rooms — and now a new City Hall report estimates the fix will be about $30 million.

“So often, the things we need to do our job are just not readily accessible,” said Lawrence Police Chief Tarik Khatib.

City commissioners at a Tuesday afternoon study session will receive a report from a city-hired consulting group that spells out the space needs of the Police Department for the next 20 years. The report recommends a new 40,000 to 50,000 square foot police headquarters building with a price tag of about $28 million to $29 million. The report doesn’t yet recommend a site for the facility, nor does it spell out a funding plan for the project.

That will be up to city commissioners as they embark on the 2013 budget process.

“We don’t have this money in any budget,” said City Commissioner Mike Dever. “I don’t think we have any easy way to pay for it.”

Commissioners may not have to fully figure out how to pay for the project during this upcoming budget process. City Commissioner Hugh Carter, who pushed for the facilities study, said he simply wants the city to come up with a multiple year, “definitive” plan for when the facility can be built.

“I understand it is a huge project,” Carter said. “The plan may be two, three, four years out for us to break ground, but I can’t see us stretching it farther than that. We’re talking about a core, public safety service here. We have to address this.”

The report, conducted jointly by Wilson Estes Police Architects and Lawrence-based Treanor Architects, found the Police Department’s forensic areas were “grossly undersized,” areas to prepare for special operations were unavailable, interview rooms often weren’t adequately private, and office conditions were extremely cramped.

“When you walk into the Police Department’s actual working environment, there is a disconnect between the level of professionalism they are providing and expected to provide versus the conditions they’re working in,” Carter said.

In addition to just a general expansion of workspace, the report recommends a new facility include several features:

• Three times the amount of forensics and crime laboratory space to do DNA analysis, photo processing, computer forensics, and evidence review.

• A basement-level parking garage large enough to store the department’s vehicle fleet. Khatib said covered parking can be important to protect patrol vehicles and the approximately $25,000 worth of equipment in each car from constant exposure to weather conditions.

• A doubling of support spaces such as locker rooms, staff fitness areas, lobby space and multipurpose training areas.

• A tactical training range that will allow for firing of live weapons and allow for the ability to “introduce smoke and sound, as well as set up vehicles and props” to simulate real world scenarios for training purposes.

Currently the department’s 181 employees are split between the Judicial and Law Enforcement Center at 11th and Massachusetts streets and the Investigations and Training Center near Bob Billings Parkway and Wakarusa Drive. But the department stores equipment and evidence in three other city buildings spread across town.

Commissioners said they’ll want to hear how improvements in Police Department facilities will improve the service officers provide in the community.

“That’s how we’re really going to be able to measure the costs versus the benefits of this,” Dever said.

Khatib said he’s confident a new facility would greatly improve the efficiency of staff members, but he also said the community will need to consider increasing the size of the police force in the near term.

“What I don’t want to have lost in all this is that we still have significant staffing issues we need to address,” Khatib said.

City commissioners will receive the report at a 4 p.m. study session on Tuesday at City Hall.