St. Louis County, MO Fence Regulations: Fence Permit Requirements (2026)
Key Facts
- No-permit height cap
- 7 feet (rear/side yard)
- Pool/spa enclosure fence
- Always needs a permit
- Electrified or barbed-wire fence
- Never permit-exempt
- Permitting authority
- Dept. of Transportation & Public Works
Summary
St. Louis County exempts fences up to 7 feet from a building permit, but pool enclosures and any electrified or barbed-wire fence need one regardless of height.
New fencing or replacement of existing fencing not more than 7 feet (2134 mm) in height, except when enclosing swimming pools, spas, or hot tubs, in the rear or side yards.
Exception: Fences of any height, which utilize electrified components or barbed wire, razor ribbon, and like material are not exempt from permit requirements. See Section 3111 of the International Building Code for permits and regulations for electrified fences and fences utilizing barbed wire, razor ribbon or like material.
5. Retaining walls which are not over 3 feet (914 mm) in height measured from the finished grade on the non-retained side of the wall to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids, in which case the wall shall not be over 2 feet (610 mm) in height. A building permit is required if the wall is located less than or equal to its height from the property line or if the total height of the retaining wall and guard or fence on top of the wall exceeds 6 feet (1828 mm). Total height is measured from the top of the proposed finished grade at the non-retained side of the wall to the top of the guard or fence. Refer to Section 1807.2.4 for guard requirements.
6. Painting, papering, tiling, carpeting, cabinets, counter tops and similar finish work.
7. Prefabricated swimming pools accessory to one- and two-family dwellings, townhouses and Group R-3 occupancies which have a maximum water depth of 24 inches (610 mm),
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 85 | Traffic: Supplement 80).
Full Breakdown
Under the County's adopted Building Code, new fencing or fence replacement up to 7 feet tall in a rear or side yard is exempt from a building permit. That exemption does not cover fencing that encloses a swimming pool, spa, or hot tub, or any fence, of any height, using electrified components, barbed wire, razor ribbon, or similar material. Those installations must go through the Department of Transportation and Public Works building permit process before work starts.
Violations & Fines
Building without a required permit exposes the owner to stop-work orders and after-the-fact permit fees; pool-enclosure fences must also meet the County's pool barrier code regardless of permit status.
Frequently Asked Questions
Do I need a permit for a 6-foot backyard fence in unincorporated St. Louis County?
Does the height exemption apply to a fence with barbed wire on top?
Sources & Official References
Other rules in St. Louis County
Compare St. Louis County to another location·View the Missouri fence regulations overview
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