5 county-level rules, plus city-specific rules for 2 cities in Boulder County, Colorado.
Verified from official government sources
A building permit is required to build a swimming pool, spa, or hot tub in unincorporated Boulder County. Any structure holding water over 24 inches deep is a regulated pool and must meet the county-adopted International Swimming Pool and Spa Code (ISPSC).
Boulder County Publication B26 (2021 ISPSC — swimming pool definition)
Any structure intended for swimming, recreational bathing or wading that contains water over 24 inches (610 mm) deep.
A pool, spa, or hot tub in unincorporated Boulder County must be enclosed by a barrier meeting 2021 ISPSC Section 305. The barrier must be at least 48 inches high measured from the outside, with no gaps a 4-inch sphere can pass, and any gate must be self-closing and self-latching.
2021 ISPSC Section 305 (adopted by Boulder County)
The top of the barrier shall be not less than 48 inches (1219 mm) above grade where measured on the side of the barrier that faces away from the pool or spa, and such height shall exist around the entire perimeter of the barrier.
Beyond the perimeter barrier, Boulder County requires spas to carry an insulated cover rated at least R-12, and small compliant spas may instead use an ASTM F1346 locking safety cover or an ISPSC Section 305 barrier. All pools follow the 2021 ISPSC's construction, entrapment-protection, and electrical safety provisions.
Boulder County Building Code Amendment N1190.6
All spas must be equipped with an insulated cover that is listed to provide a minimum R-value of at least 12.
Above-ground pools are regulated the same as in-ground pools in unincorporated Boulder County. Any above-ground pool holding water over 24 inches deep meets the ISPSC swimming-pool definition, requires a building permit, and must be enclosed by a compliant 48-inch barrier.
Boulder County Publication B26 (2021 ISPSC — swimming pool definition)
Any structure intended for swimming, recreational bathing or wading that contains water over 24 inches (610 mm) deep.
A hot tub or spa holding water over 24 inches deep is a regulated pool requiring a building permit and an insulated cover rated at least R-12. Public and semi-public spas must also meet Colorado's state health regulation, which requires spa water to turn over completely every 30 minutes.
5 CCR 1003-5-4.9
Recirculation equipment shall provide a minimum turn over of ... spa/hot tub water every thirty (30) minutes.
2 cities in Boulder County have their own swimming pools & spas rules. Each link goes to that city's dedicated page with code citations.
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