St. Charles County, MO Environmental Rules: Boat Dock Permits (2026)
Key Facts
- Governing districts
- RF Riverfront and PR Park Recreational only
- Minimum river frontage
- 300 feet (RF District)
- Max height, permitted uses
- 50 feet; 75 feet conditional uses
- Setback from property lines
- 30 feet, except river frontage
- Marina lodging waterfront setback
- 150 feet minimum
- Enforcing agency
- Division of Planning and Zoning
- Violation penalty
- Up to $500/day, 6 months jail
Summary
Boat docks, marinas and piers are a permissive use only in St. Charles County's Riverfront (RF) and Park Recreational (PR) zoning districts along the Missouri and Mississippi Rivers. In the RF District a dock or marina lot needs at least 300 feet of river frontage and a 30-foot setback from property lines. The Division of Planning and Zoning enforces these limits.
B. Permissive Uses. ... 2. Boat docks, marinas and piers. ... D. Height And Area Regulations. 1. No minimum site area for all uses except for riverboat gambling vessels. The minimum site area for riverboat gambling vessels shall be no less than twenty-five (25) acres. 2. The minimum frontage along a major river shall be three hundred (300) feet. 3. The maximum height for permitted uses in this district shall be fifty (50) feet. ... 5. The minimum building line setbacks, unless specified otherwise in this Section, shall be thirty (30) feet from all property lines, except for frontage along the river. 6. The minimum building line setbacks from the waterfront for commercial lodging in conjunction with a marina shall be no less than one hundred fifty (150) feet. 7. The minimum lot width shall be two hundred (200) feet at the front building line.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4863880; v61 updated 2026-05-11; through 05-11-2026).
Full Breakdown
St. Charles County treats boat docks the same way it treats any other building use: through Unified Development Ordinance zoning districts, not a stand-alone dock permit. 115 lists "Boat docks, marinas, ferry landings, wharves, piers, and ramps for the use of leisure craft only" as a Permissive Use in the "PR" Park Recreational District. Both districts require Community Development review before construction, and the RF District carries its own dimensional table: a minimum river frontage of 300 feet, a maximum height of 50 feet for permitted uses (75 feet for conditional uses such as commercial lodging tied to a marina), a 30-foot building-line setback from all property lines except river frontage, and a 200-foot minimum lot width at the front building line.
Commercial lodging built alongside a marina must sit back at least 150 feet from the waterfront. S. Army Corps of Engineers before the Planning and Zoning Commission will act. , a private dock is not a permissive use and needs a rezoning or conditional use permit rather than a simple building permit.
Violations & Fines
Building or using a dock, marina or pier without the required district approval is enforced under Section 405.645: the Director of the Division of Planning and Zoning can inspect the property and issue a written order requiring illegal construction or use stopped, immediately for building work. Ignoring that order is a misdemeanor punishable by a fine of up to $500 per day, six months in the County Jail, or both, with each day counted as a separate violation.
Frequently Asked Questions
Can I build a private boat dock anywhere on my St. Charles County riverfront property?
How much river frontage does the RF District require for a dock or marina?
What happens if I build a marina structure without the required approval?
Does a riverfront marina need anything beyond the RF District's basic zoning approval?
Sources & Official References
Other rules in St. Charles County
Compare St. Charles County to another location·View the Missouri environmental rules overview
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