Engineering

The Engineering and Plan Review Group is responsible for the review and approval of commercial and residential plans, regulating development in the 100-year floodplain, issuing utility excavation permits, and working with residents, developers, and engineers on wastewater, stormwater, and drinking water issues, along with review of all Planning & Zoning Commission submittals.

The division is also responsible for developing and implementing the City’s Traffic Management Code.

New feature added! You may now apply for a permit directly from the below link. Not all permit types are available, yet; however, we will be rolling out new permits types in the near future.

Submit a Development Application

Apply for Commercial Site Plan
Apply for a Residential Site Plan
Apply for a Capital Improvement Project
Submit a Preliminary Plat
Submit a Record Plat
Apply for a Boundary Adjustment Plat
Apply for a Flood Plain Development Permit
Submit As-Builts

Apply for a permit

Apply for a Grading Permit
Apply for a Driveway Permit
Apply for an Excavation Permit

Account Login

Manage Projects
Pay Fees
Submit documents
Schedule an inspection
Review Progress

Find out more about the I-70 Improvement Project through O'Fallon.
Click here!

Downloadable Construction Plans

Residential and Commercial Subdivision Plans (Download CAD files) (View as PDF, 25MB)

  • Residential Plan Instructions
  • Cover sheet Residential
  • Residential Notes
  • Erosion Detail
  • Storm & Sanitary Detail
  • Water Detail 1
  • Water Detail 2
  • Pavement Detail 1
  • Pavement Detail 2

Commercial and Industrial Site Plans (Download CAD files) (View as PDF, 26MB)

  • Commercial Plan Instructions
  • Cover Sheet Commercial
  • Commercial Notes
  • Erosion Details
  • Storm & Sanitary Details
  • Water Detail 1
  • Water Detail 2
  • Pavement Detail 1
  • Pavement Detail 2

Grading Plans (Download CAD files) (View as PDF)

  • Grading Plan Instructions
  • Cover Sheet Grading
  • Grading Notes
  • Erosion Details

Recently Adopted Ordinances

The City uses a third party company to publish updates to the City Code. These updates are only updated a few times per year. The ordinances below were approved recently, and will affect projects that require the Engineering department. Please refer to these updated ordinances. Once they are updated on the City Code, then they will be removed from this list. The full text of these ordinances is available here.

  • Concrete Rock requirement - effective November 1, 2016 (Ordinance 6242; approved August 11, 2016)

Floodplain Management


Construction Inspection

This division's purpose is to review and conduct residential and commercial construction inspections of storm sewers, sanitary sewers, water mains, streets, grading, and other site development items assuring for code and approved construction plan compliance and quality of construction.

Are you a resident with a question about your final infrastructure inspection? Send an e-mail to This email address is being protected from spambots. You need JavaScript enabled to view it..


Contact Engineering staff

General Assistance This email address is being protected from spambots. You need JavaScript enabled to view it. 636-379-5596
Vicky Usery, Administrative Assistant This email address is being protected from spambots. You need JavaScript enabled to view it. 636-379-5596