How do you charge tenants for allowing a pet?

[Marc Cunningham]

Wondering how others charge for allowing tenants to have approved pets. 

There are many different ways to charge a tenant for allowing a pet: Flat additional rent per month, higher security deposit, pet admin fees, fee per pet, fee based on the weight / breed of pet, etc.

We have tried several different ways and found that charging an upfront non-refundable 'pet admin' fee works best for us. We also charge a disclosed fee against their security deposit at the time of move-out for us to perform a black-light test on the property.

What works best for you?