Stanislaus County, CA Swimming Pools & Spas: Hot Tub Rules (2026)

The County's Swimming Pool Barrier Requirements handout includes hot tubs, spas and portable spas within the definition of “swimming pool” when they contain water over 18 inches deep. That means a spa built or remodeled under a building permit at a single-family home would generally fall under the California Swimming Pool Safety Act rule requiring at least two of seven drowning-prevention features. Importantly, the handout lists a specific EXCEPTION: hot tubs or spas with locking safety covers that comply with the American Society for Testing and Materials standard ASTM F1346. A compliant locking safety cover therefore serves as the primary protection for a spa. Spa filter and heating equipment is treated like pool equipment under Zoning Ordinance Section 21.08.065(D) — it may encroach into a side or rear yard provided a net two-foot clear adjoining passageway remains, with distances between heating systems and building openings governed by the building code and manufacturer requirements. The three-foot side/rear property-line setback in Section 21.08.065(B) also applies to spas that meet the over-18-inch-deep definition. Owners should verify with the Building Permit Division (209.525.6557) whether their specific spa installation requires a building permit and which safety documentation is needed.