Mosinee, WI Swimming Pools & Spas: Fencing & Safety Requirements (2026)

Section 42-789 covers private and residential swimming pools, defined in subsection (a) as any outdoor structure holding water deeper than one and a half feet at any point. Subsection (b) exempts small storable children's pools, no more than 15 feet across with a wall no taller than 15 inches, from the section entirely. For every other pool, subsection (f) sets the barrier standard: a pool not enclosed within a permanent building must be "completely enclosed by a fence or wall of sufficient strength to prevent access," standing at least six feet tall and built without any void, hole or opening larger than four inches in one dimension, and its gates or doors must stay locked whenever the pool is not in actual use.

Paragraph (f)(2) provides the one alternative: an above-ground portable pool can skip the separate fence if it instead has a raised deck running around the entire pool perimeter with an attached, enclosed railing at least 36 inches high on top. These fencing rules sit alongside the section's setback standard in (e), which keeps pools to rear or side lots occupied by a principal building and requires the water line to sit at least six feet from any lot line, and the construction requirements in (d), which route plumbing drainage and electrical work through state code and city ordinances rather than onto a neighbor's land or into the sanitary sewer.