Upon further inspection, a plan to ensure every rental unit in the city is licensed and inspected may not have smooth sailing through Lawrence City Hall after all.

Two key commissioners on Monday said they had concerns with the latest proposal and likely would lobby to delay approval of a new rental registration and licensing program until more research can be done.

“I don’t think we have hit upon the formula yet,” City Commissioner Hugh Carter said. “As it is proposed, I think it is a long ways from what I would be comfortable with.”

City Commissioner Mike Dever also said he had questions about the latest plan, which commissioners are scheduled to vote on at their Tuesday evening meeting.

The concerns are in contrast to a late November vote, when commissioners on a 5-0 vote asked staff members to prepare a plan to begin an expanded rental registration program.

Staff members released the latest version of that plan last week. It includes:

• The program would require registration and inspection of all rental properties in the city, which number about 18,000. Currently, the city’s program only covers rental properties that are in single-family zoned neighborhoods.

• Rental units would be inspected once every three years. The city, however, is proposing a system where larger complexes wouldn’t be required to have every unit inspected, but rather a sampling of units could be inspected.

• The inspections would check for several items related to the city’s health and safety code. The inspection, though, could also be used to issue a citation related to the city’s occupancy code. No more than four unrelated people are supposed to live in an apartment in the city, or no more than three unrelated people in single-family zoned rentals.

• Every apartment in the city would pay a $15 annual license fee. Apartments also would pay a $50 inspection fee in the year that they are due for an inspection. The city is offering a partial rebate on that fee, if units average five or fewer minor violations.

• The city previously has estimated it will cost about $370,000 to expand the rental licensing and inspection program. The proposed fees are designed to allow the program to break even. The city anticipates it will need to hire five new code enforcement officers and two new administrative assistants to staff the program.

The size and scope of the proposed program is creating concern with some commissioners.

“I don’t know if additional manpower and a larger program is the way to solve the problem, but I do think there is a problem,” Dever said. “I have had experiences in the last few years that make me believe that there are some properties that need some more oversight.”

Carter also said he is confident there are some problem rental properties in the community.

“We know there are places that are fire traps, and we know there are places that are overcrowded,” Carter said.

But Carter said he worried the city may be creating too large of a bureaucracy to deal with the issue, and was wary of some of the items an inspection would focus on. The inspections would include an array of issues: barbecue grills on decks, leaky roofs, wobbly hand rails, improper egress, and dirty furnace filters, among other things.

City Commissioner Mike Amyx previously has said he also has concerns about the size and costs of the program. He said at the time of the November vote that he was uncertain he could support the program if it required every apartment unit in the city to register. He has discussed a system that would require units 50 years and older to be licensed and inspected.

Carter said he also wanted to explore a system that would only include apartments that failed an initial inspection. After the initial inspection, apartments could be added if a tenant made a valid complaint.

In January, the city hosted a public meeting on the proposed program where multiple landlords said the plan was overly bureaucratic and an overreaction to a handful of rental problems in the city.

But an expanded rental licensing program has been a major issue with several neighborhood associations. Leaders with eight neighborhood associations spoke in favor of a broader program during the commission’s November meeting.

City commissioners will consider the latest plan at their 6:35 p.m. meeting on Tuesday at City Hall.