When the mobile home park is served by either a public, private, or community sewage disposal system and by either a public, private, or community water supply system, there shall be a maximum gross density of five dwelling units per acre, the minimum area of a mobile home lot shall be 5,000 square feet, the minimum lot width at the street line shall be 30 feet, and the minimum lot width at the building setback line shall be 40 feet. Where individual on-lot sewage disposal and/or water supply is used, each mobile home shall be placed on a lot which shall meet the requirements of § 460-39 of this Part 1.