Pet urine?

The HOA states that only one pet is allowed per unit.

The lease clearly states no animals or pets allowed without prior written consent from me.  

Any advice on implementing a pet deposit?

Allowing any pets is always a crap shoot.

I know when people arrive and if they are sneaking in a pet without paying a pet fee or if more people show up than anticipated.

You do have some control of your rental properties because you choose who lives there, how much is rent, deposit, pets, etc. 

I can't defend two things about Romney. 1, the comment about how his sons were serving in their own way by helping him get elected. 2, one time he took the family and dog on a long trip - many years ago - and put the dog in the pet carrier on top of the car.I honestly don't care about his religion.

So she found a house based on a recommendation from someone at her church and was in a hurry and put her first months & last months rent (never stated it was a deposit), app fee, and pet deposit down. 

I do something similar for pets; a basic "no pets" clause, and addendum used to allow pets on a case by case basis.