If violating a law has few if any consequences, there’s not a lot of incentive to comply with that law.

In the case of Lawrence landlords, the incentive of making more money from their rental properties can easily outweigh the incentive to comply with largely toothless city ordinances that restrict the number of unrelated people living in their rental houses.

It’s good that Lawrence city commissioners are going to try to turn that equation around by making a violation of the rental restrictions painful enough to act as a real deterrent.

According to city ordinance, houses in single-family areas can be rented to no more than three unrelated people; in property zoned multifamily, the limit is four unrelated people. The ordinance isn’t particularly easy to enforce because it’s hard to prove exactly how many people “live” in a house as opposed to how many are visiting for a day or two. In fact, the city has successfully prosecuted only one overoccupancy case in Municipal Court. That landlord paid a fine of about $100.

In most cases, when city officials identify houses with too many occupants, they don’t prosecute the case or pursue fines if the landlord agrees to comply with the regulations. If these landlords were simply ignorant of the law and would comply with the regulations in the future, that strategy might work. However, the evidence is that many landlords comply with the law temporarily to avoid a fine and then over-rent the property again.

Clearly, some tougher penalties are needed. As Commissioner Bob Schumm noted, “You’ve got to make it so they are losing money on this.”

The city’s director of planning and development services noted at Tuesday’s meeting that landlords who violate tenant limits in Fort Collins, Colo., home of Colorado State University, must pay a $1,000 fine even if they agree to comply with the law in the future. A fine that size might speak to the eight repeat-offender landlords who have accounted for nearly a quarter of the overoccupancy cases in Lawrence since 2005.

An even stronger incentive that may be considered in Lawrence is a provision that would revoke the rental license of a landlord who habitually violates the occupancy limits. Commissioners also are looking at ways to make the ordinance easier to enforce, including adding language that more clearly defines what constitutes a “resident” of a rental property.

Because the evidence in these cases occurs behind closed doors, enforcement will continue to be difficult, but when a violation is proven, the city needs to make sure the penalty is more than a slap on the wrist.