Building Permit Information

St. Charles County adopted the 2015 International Building Codes with amendments, which went into effect on Monday, August 14, 2017. Due to copyright laws we cannot publish the code on this website, but you can freely view the codes online, purchase digital subscriptions, or purchase code books at Additionally you can review reference copies at the St. Charles City-County Library. 

When Is a Building Construction Permit Required?

A building permit is required to:

  • Build, add-on, alter, or repair a structure
  • Change the use of a building or structure
  • Install new plumbing, electrical, or mechanical equipment
  • Relocate plumbing, electrical, or mechanical equipment
  • Demolish a structure or part of a structure
Please review the subpages at left and information below about the various types of permits and the inspection process. To apply for a building permit, please visit the Citizenserve Citizen Access Portal.

Project Examples

Generally, projects that do require permits include:

  • Any work done within the 100-year floodplain
  • All new construction of residential and commercial structures
  • Sheds greater than 120 square feet in size
  • Finishing a basement
  • Any electrical re-wiring or plumbing changes made in a home or addition
  • Changes in building use, such as changing a residence to a business office
  • Changes in electrical service or service upgrade
  • Fences over six feet in height
  • Installation of in-ground or above-ground swimming pools or hot tubs
  • Installation of lawn sprinklers
  • Moving a mobile home into a mobile home park or onto private property
  • Replacing an air conditioning and/or heating unit
  • Replacing a water heater
  • Installing a retaining wall over 4 feet high
  • Installing an all new septic system
  • Major repairs or alterations to existing septic systems 
  • Replacement or repair of sewer laterals or water service

 Generally, projects that do not require permits include:

  • New floor coverings
  • Painting, wallpapering and plastering
  • Pumping a septic tank
  • Repairing drywall
  • Replacing existing windows (providing the opening size is not changed)
  • Replacing a light fixture or faucet
  • Replacing a roof
  • Replacing the siding of a home
  • Utility sheds less than or equal to 120 square feet without electric. There are requirements for the placement of the shed. Contact the Planning and Zoning Division at 636-949-7335 for the setbacks.


There are many more types of projects other than those listed above, some of which may or may not require building permits. If you have any questions, please contact the St. Charles County Building and Code Enforcement Division at 636-949-7345 or if you have any questions.