You should probably have one just inside the house (maybe by the kitchen sink, if that's still in the original place), and also one near the boundary with the street, although as others have said the latter might be shared (or, in our case, under concrete from when the previous occupants widened the drive ). But there's usually one inside as well.
The water company might be able to help - v nice man eventually came out to try and help us locate our external tap when I pleaded nicely on phone (not that he could remove the concrete).