service dogs

[Jeff J.]

Just received a call : "It says you accept cats but do you accept service dogs?"

I said "we accept cats but not dogs."

After I hung up I thought "whoops I should not have said that since I can not refuse a service dog because of ADA." 

Anyway, for future reference if a prospective tenant needs a service dog what paperwork do I need from them to verify it is a service dog?

Comments?

Thanks

Jeff