Liability Question: Water Damage to Access Road

[Skyler Massey]

The waterline from the meter to one of my rental properties eroded and caused a little sink hole on a city access road that passes by my property. The property was vacant and we didn't know about the leak until a neighbor's  enclosed trailer was damaged when they tried to pull it down the road. 

The city told the trailer owner to contact us since it was our leaking pipe that caused the damage to the road. We don't own the road or the property where the damage occurred. I'm trying to figure out if we have any liability to help cover the damage for the trailer owner. It sounds like the trailer axel was bent among other things. 

I called my insurance company and they wouldn't give me an opinion until I filed a claim. I don't want to file a claim if I don't have any liability though. 

To potentially complicate the matter, we have since sold the home and cancelled the insurance policy. The damage occurred a little before we sold the home, and we hadn't heard anything from the trailer owner for several weeks. As such, we figured the trailer owner had taken care of the damage.

Does anyone know if I have any liability for the damage that occurred to the trailer? 

Any help and advice would be much appreciated. Thanks!