(a) For all uses other than single-family residential structures, plans showing layout and design of all off-street parking areas shall be submitted to and approved by the Building Official prior to issuing a building permit, and provisions for storm water drainage into an established drainage ditch or covered storm sewer system on public right-of-way shall be required for all parking lots more than 2,000 square feet in area. These provisions shall be consistent with and in consideration of the city's overall storm drainage system and future plans. Before approving any parking layout, the Building Official shall satisfy himself that parking spaces provided and storm drainage design is usable and meets standard design criteria of the city.
(b) In the case of multiple uses associated with a site, the Building Official may calculate the parking requirement as the accumulative requirement of the separate uses unless it is determined that the uses generate overlapping parking demand.