The PM is absolutely negligent. 

The problem wasn't due to your negligence and they took responsibility for the utility use so it's fair for them to suck it up.

If you haven't been negligent, I don't see how his suit against you can stick. 

If you have a liability claim situation and the attorney for the other side is taking a negligence angle against you there is a possibility they can pierce the LLC and come after you personally above and beyond what your insurance policy pays out which is why having a quality insurance policy up front is the best defense.

However, if it was me and a friend doing the project, gross negligence would have to be proven. 

So if you want your accountant to argue it out with one of the other accountants, that's fine...but not really something I want to get into the middle of.Let's assume that you are right (and that you are also right that UDFI penalties would be negligible).

Columbus doesn't issue an ordinance for this but as a landlord you can potentially put yourself in a messy situation if your tenant falls on the property due to your negligence of removal. 

We are going to fix the leak in good faith, but it’s been a year, it was obviously working when they moved in, and caused by their negligence one way or another.

It appears that your management company was negligent.

Now if the inconvenience was caused by your negligence, then that's a different story.