The road construction program in every new subdivision shall include such grading and such drainage systems as required for the proper drainage of surface water through the entire subdivision in accordance with Title 7 of this Code. When open ditches are permitted for surface water drainage, they shall not be more than four feet (4') below the established grade.
When lots are less than forty thousand (40,000) square feet in area, storm sewers shall be required which discharge into natural and/or artificial drainage channels.