St. Louis County, MO Fence Regulations: Height Limits (2026)
Key Facts
- No permit
- 6 ft or less
- Permit threshold
- Over 6 ft
- Sight triangle
- 30 ft from intersection of property lines
- Prohibited
- Barbed wire, electrical fencing (residential)
- Maintenance
- §1110.302.7
Summary
Fences 6 feet in height or less may be installed in unincorporated St. Louis County without a building permit, so a standard privacy fence goes up without county permitting. Anything taller needs a permit. Two limits apply no matter the height: barbed wire and electrical fencing are not permitted in residential areas, and a fence on a corner lot cannot sit inside the sight distance triangle.
Fences, six (6) feet in height or less, may be installed without a building permit. … Fencing located on a corner lot cannot be located within the sight distance triangle. A sight distance triangle is defined as the area of a corner lot bound by the property lines and a line connecting the two (2) points on the property lines thirty (30) feet from the intersection of the property lines. Barbed wired and electrical fencing is not permitted in residential areas.
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
The permit exemption is not an exemption from the rest of the rules. 7, which means structurally sound, no peeling or flaking paint, and no rust. A leaning, rotted, or rusting fence is a violation whether or not it ever required a permit. The sight distance triangle is defined precisely enough to measure in the yard. On a corner lot, find the point where the two property lines intersect, mark a point on each line 30 feet back from that intersection, and draw a line connecting the two marks.
The triangle bounded by the two property lines and that connecting line has to stay clear of fencing. It is a visibility rule for drivers approaching the corner, so it binds a low fence exactly as it binds a 6 foot one. The material bans are flat prohibitions in residential areas: barbed wire and electrical fencing are not permitted, so an agricultural style top strand or a charged wire is out even on a large residential lot. Underground pet containment systems are treated differently from above ground electrified fencing. These are the unincorporated county rules, and a municipality inside the county can set its own fence limits.
Violations & Fines
Enforcement runs as a Notice of Violation under §1110.302.7, and the county can order removal of barbed wire, electrified fencing, or a non-conforming fence. Fines run up to $1,000.
Frequently Asked Questions
Do I need a permit for a 4-ft fence?
Can I put up an electric pet-containment fence?
I am on a corner lot. How far back does my fence have to stay?
My fence is solid but the paint is flaking. Is that a violation?
Sources & Official References
Other rules in St. Louis County
How St. Louis County compares: Cities That Allow the Tallest Residential Fences·Compare St. Louis County to another location·View the Missouri fence regulations overview
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