Except as otherwise provided for in this title, at least one side of each lot used as a dwelling site shall abut upon a street which has been designated or dedicated to the public for street purposes, and the length of such abutting side measured at the setback line shall be at least as great as the width required for dwelling sites in the zone on which such building site is located. (Ord. 6-18-81A, 6-18-1981)