Adding square footage

[Joseph Harr]

How do you know if you'll be legally allowed to convert a detached garage into living space or create any other type of square footage increase: attached garage conversion, basement or attic conversion, ADU, etc. Do we just need to ask the city about every property we're interested in or do we need to wait until we're under contract on a specific property? Or should we ask every city we might buy in what their laws allow. I've found a few houses with these additions or conversions and when I check with the city, there were never permits so I know a lot of people just do it anyway.