Depth and width of properties reserved or laid out for industrial, business or commercial purposes, including churches, schools, stadiums, auditoriums, hospitals, clinics, libraries, fire stations or other institutions, shall be adequate to provide the off-street service and parking facilities required by the type of use and development contemplated. No such structure shall occupy more than fifty percent of the lot or land area upon which such building or structure is erected and an additional area of the lot shall be set aside for adequate off-street parking area and be paved with a hard-surfaced, dustproof material. The parking area shall be adequately drained and connected to a City storm sewer in accordance with plans having the prior written approval of the City Manager.