O'Fallon, MO Swimming Pools & Spas: Fencing & Safety Requirements (2026)
Key Facts
- Barrier required
- Around all pool and spa areas
- Mesh fencing
- Not allowed; § 305.2.4 deleted
- Vertical picket spacing
- Max 1 3/4 inches
- Horizontal rail rule
- Under 45 inches apart must face pool side
- Height exception
- Fences 54 inches or taller exempt
- Spa exemption
- Lockable ASTM F1346 cover exempts barrier rules
Summary
O'Fallon's adopted Swimming Pool and Spa Code requires a barrier around every pool and spa area, spelled out in amended Section 305 of Section 500.560. Vertical fence pickets cannot be spaced more than 1 3/4 inches apart, and horizontal rails under 45 inches apart must face the pool side, unless the fence stands 54 inches or taller.
(SECTION 305 BARRIER REQUIREMENTS) 305.1 General. The provisions of this Section shall apply to the design of barriers for restricting entry into areas having pools and spas. Where spas or hot tubs are equipped with a lockable safety cover complying with ASTM F1346 the areas where those spas or hot tubs are located shall not be required to comply with Sections 305.2 through 305.7. 305.2.4 Mesh fence as a barrier. Delete in its entirety. 305.2.4.1 Setback for mesh fences. Delete in its entirety. 305.2.5 Closely spaced horizontal members. Where the barrier is composed of horizontal and vertical members, and the distance between the tops of the horizontal members is less than 45 inches (1,143 mm), the horizontal members shall be located on the pool or spa side of the fence. Spacing between vertical members shall not exceed 1 3/4 inches (44 mm) in width. Where there are decorative cutouts within vertical members, spacing within the cutouts shall not exceed 1 3/4 inches (44 mm) in width. Exception: Any fence that is 54 inches in height or greater.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4860992; v58 updated 2026-05-14; through 05-14-2026).
Full Breakdown
560, which amends Chapter 3 of the 2021 International Swimming Pool and Spa Code. 7. 1, in their entirety, so a mesh pool fence that would satisfy the unamended national code does not satisfy O'Fallon's local version. 5 sets the picket spacing: where the gap between the tops of horizontal rails is less than 45 inches, those horizontal members must sit on the pool side of the fence so they cannot be used as a foothold to climb over, and the vertical members, or any decorative cutouts within them, cannot be spaced more than 1 3/4 inches apart.
That climb-resistant spacing rule does not apply once the fence reaches 54 inches or taller. 550, and a barrier that does not conform can hold up final approval to fill and use the pool.
Violations & Fines
Installing a pool or spa without a code-compliant barrier, or with a deleted-option mesh fence, is enforced the same as any other adopted pool-code violation: under Section 113.4, a fine of not more than $500 or up to 90 days in jail, or both, with each day the noncompliant barrier remains in place treated as a separate offense until it is corrected and reinspected.
Frequently Asked Questions
Is a mesh fence allowed around a pool in O'Fallon?
How far apart can pool fence pickets be?
Does a hot tub need the same fence as a pool?
Sources & Official References
Other rules in O'Fallon
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