You need to make sure you are not committing usury.  

I also now wonder if these are the type of people that would commit insurance fraud just to get a few extra dollars.

@Larry T. 

This guy has already committed to moving out of state.

The initial sales agreement is a legally binding document that commits the buyer to complete the purchase and to pay the balance of the agreed price on a specified future date.The real estate purchase process is overseen by a notary (notario) who in Italy typically has more responsibilities in the process than in many other countries of the world (e.g. title search,).

I would hate for you to commit an act of discrimination based on anything we tell you.

:@Joe T....  

If the dog does cause damage, the tenants are responsible for that damage...like any other damage...and it can be deducted from their security deposit.Is it complete and total bulls**t that this particular dog is an emotional support animal? 

Or as @Jr T. said your last bill may have been estimated, or this is the first bill that actually has your water use on it since they bill quarterly and you have only been there 6 months, assuming the home was vacant previously.

If you have to pull the plug on the deal, it's better to lose a little on a bad deal that doesn't happen then commit and continue to throw good money after the bad money.