Preliminary Plat

How Do I Apply?

Please visit the Land Development & Zoning Applications section of our Citizenserve Citizen Access Portal.

By applying, the applicant authorizes the Community Development Department’s staff, or staff of other agencies at the Department’s direction, to enter and inspect the subject property for the purposes of processing the application. This authorization will cease upon final resolution of the application.

When is a Preliminary Plat Required?

A Preliminary Plat, once approved by the Planning and Zoning Commission and Planning and Zoning Division Director, enables the developer to:

  • Obtain County approval of engineered subdivision improvement plans
  • Construct public improvements and other infrastructure in accordance with approved improvement plans, or submit financial guarantees to ensure future construction
  • Prepare a Final Plat in accordance with the approved Preliminary Plat

No lots in a subdivision may be sold until a Final Plat for the subdivision is approved and recorded by St. Charles County.

What Will I Need to Submit?

Before preparing the detailed Preliminary Plat, the developer has the option to first submit a concept plan to County staff for initial review and feedback.

Preliminary Plats must be prepared by a land surveyor or engineer licensed by the State of Missouri and must at a minimum include the plat information specified in Section 410.110 and be accompanied by written statements required by Section 410.120 of the Unified Development Ordinance. You may wish to review the Preliminary Plat Checklist (PDF) to ensure completeness. Incomplete plat applications may be returned within 8 business days with an explanation of additional necessary information.

Complete applications must be submitted at least 27 days before the Planning and Zoning Commission meeting at which it is to be considered.

Traffic studies will be required to determine proper pavement widths for new arterial streets, and may be required for new collector streets and for commercial and industrial developments. (Section 410.330 and Exhibit A1 of the Subdivision Regulations)

When compliance with the Subdivision Regulations would impose practical difficulties or a particular hardship due to the tract’s unusual shape, size, or topography, the applicant may have grounds to apply for a variance to the subdivision regulations. Variance requests should be submitted in writing with the Preliminary Plat application, in which case both the plat and variance(s) must not only be reviewed by the Planning and Zoning Commission but approved by the County Council.


Complete applications must include payment of the fee specified in Section 405.020.H of the Unified Development Ordinance.