ADU Rules in Wildwood, Missouri

Wildwood is one of the largest cities in St. Louis County by land area, incorporated in 1995 after residents of western St. Louis County sought to control their own land use and preserve the area's rural and greenspace character. With a population of approximately 35,000 spread over a large geographic area, Wildwood is characterized by low-density development, significant natural land, parks, and greenways. Wildwood's zoning reflects a conscious community commitment to limiting density and preserving open space — a context that shapes how ADU regulations are applied. Missouri has enacted no statewide ADU preemption law.

Missouri State Law

Missouri has no statewide ADU preemption statute. Wildwood sets its own ADU rules through its local Code of Ordinances, zoning chapter.

Wildwood's Unique Development Character

Unlike many St. Louis County suburbs, Wildwood was incorporated specifically to control and limit development density in western St. Louis County. The city has:

• Large lot zoning: Many districts require minimum lot sizes of 1 acre, 2 acres, or larger.
• Rural-residential character: A significant portion of the city's land is in rural-residential or environmental protection zoning.
• Greenspace commitment: The city has an active parks and trails program and has preserved significant open land.

This context means ADU standards in Wildwood may differ from denser suburban contexts. ADUs on large rural-residential lots may be feasible in some districts, while other districts may restrict or limit accessory structures. Confirm with the Planning and Parks Department what is allowed on your specific parcel.

Permitted ADU Types

ADU types that may be permitted in applicable Wildwood residential districts include:

• Detached ADU: A freestanding structure on the same lot as the primary dwelling. Given larger lot sizes in much of Wildwood, detached ADUs may be more feasible here than in denser suburban areas.
• Attached ADU: An addition to the primary dwelling creating a separate, self-contained unit.
• Existing Outbuilding Conversion: Converting an existing barn, carriage house, or large outbuilding into habitable space, subject to building code compliance.
• Basement or Interior Conversion: Adapting existing interior space within the primary structure.

Permitted types and standards vary significantly by zoning district — from very low-density rural districts to more conventional suburban residential zones. Contact the Planning and Parks Department for your specific district.

Size, Setbacks, and Height

Dimensional standards vary by district and may be more generous on large lots. General reference:

• Maximum size: Typically subject to a square footage cap or a percentage of the primary dwelling's floor area; may vary by district.
• Setbacks: On large rural-residential lots, setbacks may be more generous (25+ feet from property lines for accessory structures); verify your district.
• Height: Detached ADUs are generally limited per district accessory structure standards; may be one or two stories in some districts.
• Lot coverage: Lot coverage limits in rural-residential districts may be expressed as a percentage of the larger lot area.

Always verify current standards with the Planning and Parks Department.

Environmental Considerations

Wildwood has significant natural features including creek corridors, wooded areas, and designated greenways. Properties near waterways or in environmentally sensitive areas may be subject to stream buffer requirements, tree protection ordinances, or other environmental regulations that affect where an ADU can be located on a lot. Check with the Planning and Parks Department for any environmental overlay requirements on your property.

Flood Zone Considerations

Some portions of Wildwood near creek corridors may be in FEMA-designated flood zones. Check FEMA's Flood Map Service Center (msc.fema.gov) for your property's flood zone status before planning any ADU construction.

Permit Process

1. Confirm zoning district: Check your property's zoning using Wildwood's online GIS portal.
2. Check for environmental overlays: Determine if stream buffers, greenways, or other overlays affect your lot.
3. Check flood zone status: Verify at FEMA's Flood Map Service Center.
4. Review Code of Ordinances: Identify ADU standards for your specific district.
5. Pre-application consultation: Contact the Planning and Parks Department to discuss your specific property and project.
6. Prepare plans: Work with an architect or designer to prepare required documents.
7. Submit building permit application: File with Wildwood's Building Division or Planning and Parks Department.
8. Plan review: Staff reviews for zoning, building code, and environmental compliance.
9. Permit issuance: Obtain permit before starting construction.
10. Inspections and Certificate of Occupancy: Complete required inspections; obtain CO before occupying.

Contact Information

City of Wildwood Planning and Parks Department 16860 Main Street, Wildwood, MO 63040 Phone: (636) 458-0440 Website: cityofwildwood.com/302/Planning-Parks

Disclaimer: Zoning regulations change frequently. Always verify current ADU rules directly with the City of Wildwood Planning and Parks Department before beginning any project. This page is for informational purposes only and does not constitute legal or zoning advice.