If it's an ordinance and someone complains (or it's one of those narc-y townships using satellite imagery and drone enforcement) then you get an inspection. If you're found in violation you'll get an enforcement notice.

It's the one reason I am so nervous about who my neighbors are when doing anything "weird" on a property. The township, city, county, state, whatever jurisdiction it falls under _will_ handle it.

Except, with 80% of new homes having an HOA, who doesn't have one?