St. Louis, MO Zoning Guide

St. Louis Zoning Code and Title 26

The City of St. Louis identifies Title 26 of the 1994 City of St. Louis Revised Code as the location of its Zoning Code. The City's broader Revised Code is organized by subject and is supplemented as new ordinances are adopted. :contentReference[oaicite:3]{index=3}

The 12 Primary St. Louis Zoning Districts

St. Louis City uses twelve primary zoning districts identified by the letters A through L. The City describes these districts as ranging from single-family residential through multi-family, commercial, industrial, unrestricted and Jefferson Memorial districts. :contentReference[oaicite:4]{index=4}

How to Find the Zoning for a St. Louis Property

The City states that current zoning for parcels is available through its Address Search. This is the correct starting point for property-specific zoning research. :contentReference[oaicite:5]{index=5}

St. Louis Setback Requirements Are District-Specific

There is no single setback number that safely answers every St. Louis property question. The City's zoning FAQ states that front, side and rear setbacks depend on the zoning district. :contentReference[oaicite:6]{index=6}

The City also explains that side-yard setbacks can be affected by lot width in certain zones and by the type and height of the proposed structure. Rear-yard requirements also vary by zoning district. :contentReference[oaicite:7]{index=7}

St. Louis Lot Size Can Affect What You Can Build

Lot size is not merely a real-estate measurement. It can interact with zoning rules governing dwelling units, setbacks and the amount of development that can occur on a property.

This is particularly important in St. Louis because the City adopted Ordinance 72027 in 2025, changing minimum lot-size rules for single-family and two-family dwellings. The ordinance became effective July 11, 2025. :contentReference[oaicite:9]{index=9}

Accessory Structures in St. Louis City

Accessory structures are one of the areas where homeowners commonly confuse zoning rules with permit rules. A structure can have a relatively small footprint and still be subject to zoning setbacks, while the building permit threshold may be different.

St. Louis states that accessory buildings over 50 square feet require a residential building permit. It also states that accessory buildings of 50 square feet or less may not require a building permit when the applicable zoning setbacks are maintained. :contentReference[oaicite:10]{index=10}

St. Louis Garage Zoning and Permit Considerations

A new garage is not simply a construction question. Its location, relationship to the rear yard or alley, zoning district and building characteristics all need to be considered.

The City explicitly lists new garages and carports among residential work requiring a building permit. :contentReference[oaicite:11]{index=11}

• Verify the property's zoning district.
• Check the applicable rear-yard and side-yard standards.
• Determine the garage's relationship to the alley or rear property boundary.
• Review whether additional zoning review applies.
• Prepare the required plans for permit submission.

St. Louis Shed Rules: Size Is Only One Part of the Question

If you are planning a backyard shed in St. Louis City, do not stop at the question of whether the shed is small enough to avoid a building permit.

The City's residential permit guidance specifically says that a small accessory building of 50 square feet or less may not require a building permit if the required zoning setbacks are maintained. :contentReference[oaicite:12]{index=12}

St. Louis Deck and Porch Requirements

Deck and porch projects deserve separate attention because they can affect both the building envelope and the structure itself.

The City lists porches and decks among residential work requiring a building permit. :contentReference[oaicite:13]{index=13}

Does a Fence Need a Permit in St. Louis City?

The City states that all new fences of any type require a building permit, with an exception for replacement of existing fencing when it remains the same height, material and location in the rear or side yard. :contentReference[oaicite:14]{index=14}

St. Louis Pool Permit and Zoning Considerations

Pool projects have a specific permit threshold in the City's residential guidance, but the answer depends on dimensions and construction characteristics.

St. Louis lists swimming pools more than 24 inches deep or more than 30 inches in wall height and with a surface area of at least 250 square feet among work requiring a building permit. The City also identifies structural work and permanently equipped circulating systems as permit-triggering circumstances. :contentReference[oaicite:15]{index=15}

St. Louis ADU Zoning Rules Changed in 2025

Accessory dwelling units deserve special attention because St. Louis changed its zoning framework for ADUs through Ordinance 72036.

The ordinance, effective September 29, 2025, amended the Zoning Code to define and regulate attached and detached ADUs and permits them by right in all residential zones, subject to the ordinance's specific site requirements. :contentReference[oaicite:16]{index=16}

Historic Districts Can Add Another Layer of Review

St. Louis property owners should check historic status separately from ordinary zoning and building-permit requirements.

The City states that properties located within a City Historic District or designated as a City Landmark can require Cultural Resources approval for exterior work that might otherwise fall outside normal building-permit requirements. Examples listed by the City include exterior painting, gutters and downspouts, windows, doors, tuckpointing, fences and awnings. :contentReference[oaicite:17]{index=17}

Flood Zones Can Create Additional St. Louis Requirements

Zoning is not the only local consideration. The City specifically warns that properties in designated flood areas can require additional approval.

According to the City's residential permit guidance, construction projects located in a FEMA floodway or FIRM-designated flood area require a Floodway Development Permit even where a building permit might not otherwise be required by the Building Code. :contentReference[oaicite:18]{index=18}

Zoning Approval and a Building Permit Are Not the Same Thing

This distinction is critical. Zoning determines whether a proposed use and development arrangement comply with land-use rules. A building permit authorizes construction after the applicable building requirements and reviews have been satisfied.

St. Louis states that its building permit serves as formal legal authorization to begin construction, while zoning staff reviews building and occupancy permits for compliance with the Zoning Code. :contentReference[oaicite:19]{index=19}

One St. Louis Project Can Need Multiple Permits

A building permit does not necessarily cover every trade involved in a project. The City states that some projects may also require separate plumbing, mechanical or electrical permits. :contentReference[oaicite:20]{index=20}

How to Research a St. Louis Property Before Building

Common St. Louis Zoning Mistakes

Check Your St. Louis Project Before Construction

Different projects trigger different zoning, building and trade questions. Permitrust covers nine common residential project types so you can research the requirements around the work you actually plan to do.

St. Louis Official Zoning & Permit Resources

Permitrust is a research tool, not the government permitting authority. For a final project decision, confirm the applicable requirements with the City of St. Louis.

St. Louis Zoning FAQs