Grading Plan Requirements - Type I
Permit Application for Residential Addition, Accessory Structure, Swimming Pool, etc.
For Properties Not Within Special Flood Hazard Areas
(Disturbed area less than 5,000 square feet)
Application for a building permit for improvements fitting the above description shall submit the following:
Two copies of a site grading plan prepared by a professional land surveyor or engineer registered in the State of Illinois. The site grading plan shall be based on a boundary survey prepared within the past year. The site grading plan must be at an appropriate scale (e.g.: 1"=10', 1"=20’, or 1”=30”); reduced copies will not be accepted. The grading plan must show ground topography and structure foundations by elevations and maximum one-foot contour intervals over the site and including all areas 100 feet beyond the site. Topographic information on the site and areas abutting or adjacent to the site must show existing drainage patterns and the drainage course that may affect, or be affected by the development of the site. This may require additional topography and/or extensive stormwater drainage studies.
- The site grading plan shall indicate and label all existing and proposed structures with dimensions, including setback distances to property lot lines.
- The site grading plan shall indicate all existing and proposed utilities and easements. Additions that include a new sump pump discharge(s) and/or all new sump pump discharges, must provide a 4” minimum diameter, storm sewer service, connected to a storm sewer and must discharge the sump pump(s) into this service or construct a drywell per city standards and discharge the sump pump(s) into the drywell, if a storm sewer is not available.
- The site grading plan shall be based on a benchmark referenced to DuPage County datum and shall show the existing top of foundation elevation of the principal structure on the property. In cases where extensive grading, depressional storage, or other such special drainage conditions exist, a final grading survey indicating compliance with the grading plan must be submitted prior to the issuance of a certificate of occupancy. A security deposit shall be required to ensure compliance with this permit requirement.
- The site grading plan must show the location of all existing structures and land features abutting or adjacent to the site (sheds, garages, fences, etc.) including their top of foundation and finish grade elevation.
- The site grading plan must show the proposed top of foundation elevation at least six inches (6”) above the finish grade elevation of the proposed improvement. Six inches (6”) of the concrete foundation must be exposed and water must drain away from the structure.
- The site grading plan must show proposed drainage patterns or drainage courses by depicting any changes in grade elevation by illustrating proposed (solid or bold lines) and existing (dashed or fine lines) contours and/or elevations (such as garage floors, swales, property corners, and property lines).
- The site grading plan must show all other proposed site improvements such as driveways, patios, and/or service walks with proposed grades.
- The site grading plan must show a temporary hard surface construction access route must be shown on the plan using gravel or other hard surface material, which must be installed prior to excavation.
- The site grading plan must show a perimeter silt fence and provide a silt fence detail.
- The site grading plan must show a concrete washout location and provide a concrete washout detail.
- All Development Projects are now required to have an Impervious Area Calculation as per the revised DuPage County Stormwater Ordinance. The calculation should follow the following example and be all impervious area that is on the property. (Note: In some cases the Net New Impervious Area IS negative)
- On projects that include more than 2,500 square feet of net new impervious areas, Volume Control and Post Construction BMP’s shall be designed and installed pursuant to sections 15-64 &15-65 of the Countywide Stormwater Management Ordinance.
- The land surveyor or engineer preparing the grading plan shall investigate and identify any local topographical depression and include the high water elevation and overflow location(s) on the site grading plan. A statement shall be added to the plan that the land surveyor or engineer has reviewed and identified any local topographical depression. Furthermore, the land surveyor or engineer shall certify that the proposed improvements have been designed so as to not displace any ponding or standing water, or not change the drainage of surface waters, or that adequate provisions have been incorporated into the site grading plan so as to not adversely affect the drainage of stormwater to, or from, the site and abutting or adjacent properties.