TX- Do I need to honor a verbal agreement my current tenants had with the previous landlord?

A written agreement overrides any verbal agreement---it would have sure been better to iron this out when you took over but whats done is done. Their is no law to cite-the contract states fact and the verbal agreement holds no merit especially since it was made with a previous owner. I wonder who's name is on that water bill ? It certainly should be in the tenants name and hopefully not yours--that will also determine who is responsible should you and the renter get in a stand -off. You might want to strike up a compromise with your tenant if you aren't prepared to lose them right now---no water is a health issue and they cant stay more then a day or two....