Residential storage sheds shall be allowed within the required rear and side yard setbacks in all residential zones provided they are no closer to the front lot line than the rear building wall line of the residential structure and provided they are set back a minimum distance of five feet from rear and side lot lines. Residential storage sheds may be located closer to the front lot line than the rear building wall line of the residential structure provided they do not encroach upon the required side yard setback. Under no circumstances shall they be permitted within the required front yard setback.