How to expense/write off a huge water bill

[Amit M.]

Recently my tenant received a very huge water bill due to a busted pipe under the slab. There were no visible signs of  leak above the ground. I got the whole house re-piped and  intend to cover the excess usage due to the leak. The problem is that the water bill is in my tenants name. If I pay  his water bill how do I expense that in my tax returns. Instead, if I ask him to take off a certain amount from the rent check every month and pay that towards the water bill, would that be a good idea ? Should this arrangement be done in some kind of an agreement ?

I do intend to consult a CPA but wanted to have some understanding of possible options before I interview a CPA

Thanks

AM