Except as provided for in section 12.12.030, lots serviced by a public sanitary sewer system shall have a minimum frontage of 75 feet in width at the front lot line except in the R-6 Urban Single-Family Residential District and the R-12 Mobile Home District, and except as provided for in section 12.12.030 the width of all lots located on land with soils suitable for the use of an on-site soil absorption sewage disposal system shall not be less than one hundred-fifty (150) feet and the area of all such lots shall not be less than forty thousand (40,000) square feet per dwelling unit to be constructed on the lot. Such on-site soil absorption sewage disposal systems shall be designated in accordance with all state and local laws, regulations and ordinances. On-site sewage disposal absorption systems shall be located on the same parcel of land as the building or buildings which are serviced by it. [Code § 12.10-2.]