Missouri Retaining Wall Permit Requirements

Statewide Building Code

Missouri does not enforce a uniform statewide building code. Instead, building regulations are adopted and enforced at the local level. Most municipalities follow the International Residential Code (IRC) and the International Building Code (IBC)—often the 2018 edition or more recent—with local amendments. Always consult your city or county building department to confirm the applicable code.

R404.4 Retaining Walls – IRC 2018

According to Section R404.4 of the IRC:

  • Retaining walls not laterally supported at the top and retaining more than 48 inches (1219 mm) of unbalanced fill must be designed according to accepted engineering practices.
  • Retaining walls over 24 inches (610 mm) that support additional lateral loads (e.g., slopes, adjacent structures) also require engineered design.

These provisions ensure structural safety, drainage, and performance of walls retaining significant soil loads.

When Is a Retaining Wall Permit Required?

In Missouri, permit requirements vary by jurisdiction, but generally:

  • A building permit is required for retaining walls over 4 feet tall (measured from the bottom of the footing to the top of the wall).
  • A licensed professional engineer must design such walls.
  • Walls under 4 feet that do not support a surcharge may not require a permit.

Check with your local building department to determine whether your project is exempt or requires review.

Front Yard Setback Requirements

Setback rules are governed by local zoning ordinances and often depend on lot size, street classification, and structure height. For instance:

  • In Kansas City, setbacks vary by zoning district and can be found through the Zoning & Development Code.
  • In St. Louis, setback information is available via the City’s Zoning Administration.

For exact requirements, contact your city planning or zoning department before starting work.

Local Jurisdiction Requirements

St. Louis

  • Permit Requirement: Required for retaining walls over 4 feet.
  • Contact: Building Division
  • Notes: Engineering required if wall supports surcharge or exceeds height threshold.

Kansas City

  • Permit Requirement: Walls over 4 feet require a permit and engineered drawings.
  • Submit: Via Compass KC Portal
  • Zoning Info: Kansas City Zoning Code

Springfield

  • Permit Requirement: Required for walls taller than 4 feet.
  • Contact: Building Development Services
  • Submittals: May include engineered drawings and site plan.

Columbia

  • Permit Requirement: Required for walls over 4 feet in height.
  • Contact: Community Development Department
  • Resources: Residential permit guide

Missouri does not have a uniform statewide code, but most local jurisdictions follow the IRC and IBC. Retaining walls over 4 feet or those supporting a surcharge generally require:

  • A building permit
  • A design from a licensed professional engineer

Front yard setbacks and other zoning requirements vary by city, so always check with your local building or planning department before beginning work. Learn more about our engineering services in Missouri here.