Pool House Conversion to Living Space: Title 24 Requirements
A pool house is usually plumbed already, so the first question is whether it is conditioned today. If it is, turning it into living space or an ADU is an alteration. If it is open or unheated, it is an addition. Only the conditioned part counts, which matters when an equipment room shares the building.
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Is it conditioned today?
The Commission's ADU guidance names a conditioned pool house repurposed as an ADU as an alteration, because it does not increase conditioned floor area or volume. A cabana that is open or unheated is different: heating or cooling it is newly conditioned space, an addition.
Only the conditioned part counts
Conditioned floor area is measured at the exterior surfaces of the walls enclosing conditioned space. In a pool house with a lounge and a pump room, only the lounge counts toward the size bands of 400 and 700 square feet. In an addition, the wall between the two separates conditioned from unconditioned space, so it is an envelope wall and takes at least the mandatory insulation of Section 150.0(c), R-15 in 2x4 framing or R-21 in 2x6; ask how the prescriptive wall value applies.
Hot water for the new bathroom
In an addition, an additional water heater must be a heat pump water heater not placed outdoors and set on an R-10 base, a unit meeting NEEA Tier 3, or, at 500 square feet or less, an electric heater with point-of-use piping under Appendix RA4.4.5. The Commission's example allows up to 10 feet of half-inch pipe or 15 feet of three-eighths-inch pipe. In an alteration, a new water heater meets the alteration rules of Section 150.2(b)1H instead. A new bathroom needs local exhaust either way.
Pool equipment follows its own rules
The heater, cover, pump and filter are regulated as pool equipment whether or not the building is converted; see pool and spa requirements. If the unit needs an enclosed entry or stair, HCD allows an ADU in an existing accessory structure to grow by up to 150 square feet for access, and any enclosed, conditioned part of that growth adds floor area and volume.
Related pages: accessory structures, guest house conversions, detached studios and ADU heat pump water heaters. See our ADU Title 24 reports.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
No. The Commission calls it an alteration, because no conditioned floor area or volume is added. Only altered components must meet the alteration rules.
Only if it is conditioned. Conditioned floor area counts enclosed conditioned space, measured at the exterior surfaces of the walls around it.
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View all Additions and Remodels guides → · Permits and Compliance · Title 24 guide