service dog and weight restrictions

[Aaron Davis]

So we have a clear pet policy that states a 30lb restriction. Tenants moved in with puppy (turns out to be part rottweiler). Now they tell me that they've registered the dog as a service dog, shown me papers, doctors note, etc. I'd it possible to still enforce the weight restriction without violating antidiscrimination laws or fair housing?II should add these are apartments so there are more tenants to consider.