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

In unincorporated Sonoma County, Permit Sonoma guideline CNI-044 defines a 'private swimming pool' to include any in-ground or above-ground structure designed for swimming or bathing that contains water exceeding 18 inches deep. Because most spas and hot tubs exceed that depth, they fall under the same permit and safety framework as pools. When a building permit is issued for a new or remodeled spa at a single-family home, California Health & Safety Code 115922 requires at least two of seven drowning-prevention features. An approved safety cover meeting ASTM F1346-91, with electric controls at least 60 inches above grade, is one accepted feature and is commonly used for spas; an isolation enclosure, door alarms, self-latching door devices, and water-surface alarms are other options. Spa electrical work must meet the same GFCI, bonding, and receptacle-clearance standards as pools per CNI-044. Owners of self-contained portable spas should still verify with Permit Sonoma whether the unit needs a building or electrical permit, since hardwired 220-volt connections generally require electrical permitting even if the spa shell is portable.