St. Charles County, MO Environmental Rules: Erosion Control (2026)

St. Charles County Code Chapter 412 governs erosion and sediment control on unincorporated land undergoing non-agricultural development. 010 states the purpose is to control soil erosion, preserve natural terrain and waterways, and prevent degradation of water quality and obstruction of stormwater flows in storm sewers, road ditches and natural watercourses. 020 requires anyone proposing to remove ground vegetation, disturb or fill land, or store soil in the unincorporated county to apply to the Department of Community Development for a land disturbance permit; stricter state or federal permit conditions govern where they exceed the county standard.

040 sets the trigger: land disturbance activity affecting 5,000 square feet or more requires the permit before work starts. 050 exempts right-of-way work under a special use permit, public utility installation and repair, quarries and permitted landfills that do not drain off-site, farming and landscaping done to soil conservation standards, resodding under 10,000 square feet, ordinary gardening on one- and two-family lots, emergency work protecting life or property, and specified levee repairs, provided none of these change drainage patterns or cause sedimentation onto neighboring land.

130. A performance guarantee covering the cost of erosion and sediment controls must be posted before a permit issues and can be forfeited to fund pollution-prevention work if a violation goes uncorrected.