(CBS) — When Fido does his business, and nobody cleans it up, the city of Chicago may now go after not just the dog owner, but the property owner as well.

The fines could be staggering, CBS 2’s Mike Parker reports.

“It’s a quality of life issue for neighbors, and it’s feeding the rats,” says first term Ald. Carlos Rosa, Ward 35, defending his proposed ordinance that could fine property owners up to $500 for letting dog waste accumulate in their yards.

“I’ve had constituents who say, ‘Alderman, I have to close my windows all summer long and I have to seal them with tape, because my neighbor has his backyard full of dog excrement,’” he says.

The former head of the city’s Animal Control department is vowing to fight the proposal. Cherie Travis is the owner of several rental buildings.

She predicts many landlords will stop renting to dog owners, and when that happens they won’t be able to get rental units.

“I foresee a spike in the number of dogs that will turned in to Chicago animal control. … My prediction is it would increase the number of animals that would be euthanized,” Travis says.

But supporters of the proposal, including Mayor Emanuel, believe more than anything it’s a measure to battle the invasion of rats in the city.

Rat complaints are up dramatically, and dog waste is known to attract them.