[KeepFlying]

In the US it's the Fair Housing Act. Basically if the dog is providing necessary emotional support then the landlord can't prevent them from being with you in your home (I think there might be a carve out for nuisance dogs, but the dog doesn't need to be specifically trained for anything in particular to qualify).

It's a really low bar for a dog to qualify as an Emotional Support Animal. Which is great for people who need it, but is SO easy to abuse.

It only gives permission for someone to live with their dog though. It doesn't give someone any rights to bring their dog to restaurants and stuff though, even though people try. That's reserved for Service Animals.

[lotsofpulp]

Service dog is also SO easy to abuse.

What service does your service dog perform?

It alerts me to seizures or tells me when to take my diabetes medicine.

[KeepFlying]

Your dog still needs to be under control though. The ADA is somewhat vague on what that means but it is a behavior standard and if someone's dog is misbehaving you can kick out the dog (the human needs to be allowed to return without the animal).