Go deep, my companion.

We have a single family home that's been modified and now has an attached companion unit with its own kitchenette, bathroom and side entrance. 

Andrew a quick clarification here....there are actually two related and distinct categories of units listed within City of SD; Companion units and Junior units....While the Junior units do require owner occupancy, the Companion units regs do not list that as being required.

For a great companion read, check out The Big Long, written by Waypoint founders Colin Wiel and Doug Brien.

My other building has had no issues, other than one "companion animal that was needed."

I am not sure if there is a companion form/law for property management, but I am sure there are general privacy laws.

A "companion animal" is an animal that people can get because their doctor says it will help them.I have some opinions I tried to keep out of this but each of the three require their own distinct method of working with and documenting in your leases and in your dealings with tenants.  

so, considering that even if the tenant is neither blind nor deaf nor mobility impaired, there may now be a plethora of other instances in which suddenly turning away 'pets' can easily develop into a lawsuit for 'discrimination' and suddenly the pet is a 'therapy aide' or whatever, so what sort of documentation would be adequate enough to distinguish a bona-fide service/alert/therapy dog, from a dog that grandma simply wants have around as a.. companion that comforts her and makes her feel better just having around (which is what a pet is, aint it?)

Are emotional support, therapy, comfort, or companion animals considered service animals under the ADA?

And the organization is very passionate that we should demand all animals, including companion animals be neutered as part of the lease.