California Title 24 and New Pool Construction

Every pool permitted in California since January 1, 2026 is built under the 2025 Energy Code, and that code will not let gas be a pool’s primary heat source. A pool being built for the first time has never been heated, so the exception that protects existing heated pools cannot reach it. If your pool is going to be heated, and nearly every pool we build is, the heater has to fit one of five approved pathways. In practice that means a heat pump or solar collectors.

A renovation is a different animal, which is where most people get turned around, and almost everything written about this in 2025 was built around a permit deadline that has since passed. For new residential pool construction anywhere in the Bay Area, the rules now run like this.

Does the New Code Apply to My Pool?

The trigger is the day your permit application goes in. Not the day the excavator shows up, and not the day you fill the pool. State law ties a permit to whichever standards were already in effect locally when the application was submitted. So applications filed on or after January 1, 2026 follow the 2025 Energy Code, and anything filed on or before December 31, 2025 was reviewed under the 2022 edition.

Codes turn over every three years, so this edition should hold for projects permitted through the end of 2028. Filing is also the moment your project’s rules stop moving, which is a decent argument for a complete application over a fast one. That is step three of our build process.

Does the Existing-Pool Exception Cover a New Build?

No. The sizing rule carries five exceptions, and the one everybody quotes at us is the alterations exception. It is written for alteration work on a pool that already has heating equipment installed. Nothing is installed on a hole that has not been dug yet. So it never reaches new construction.

That holds whether the pool goes in beside a house still being framed or one that has stood since 1974. New construction, additions, alterations: the code lands the pool requirements in the same place in all three. No scope table drops the heating rule for a first-time pool.

One honest caveat, better from us than from your plan checker. The rule sizes a heating system, so it only engages if the pool is going to be heated. A pool with no heater sits outside it, and a separate exception covers solar-only heating with no backup. Both are rare around here.

So What Is Allowed to Heat a New Pool?

Five options, and your system has to satisfy one. Solar collectors covering at least 60 percent of the combined pool and spa surface on a single-family lot, or 65 percent on multifamily and commercial. A heat pump carrying the primary load, sized to the energy code’s heat pump sizing appendix, with a supplementary heater on any fuel you like. On-site renewable or recovered energy supplying at least 60 percent of the heater’s annual consumption. Solar and a heat pump together with no supplementary heater at all. Or an alternative the Energy Commission’s Executive Director has judged at least as efficient as those four.

Now read that list for what is missing. Nothing on it burns gas as the main event, and nothing uses electric resistance. No clause anywhere bans gas outright. The silence does the work. Gas sitting behind a compliant heat pump as a booster is still entirely legal.

On an existing pool the solar pathways are mostly theoretical, because the roof and the yard are already committed. On a new build they are live options, which is the real argument for settling heat at the design table instead of the equipment order. That 65 percent figure governs our commercial pool construction work.

What About the Spa?

If the spa shares a heater with the pool, it is one pool and spa system and the sizing rule covers the whole thing. The exception people reach for is the one written for permanent spas. It allows gas for a heater used exclusively for a spa, and it reaches existing buildings only, so a spa going in with a newly built home cannot claim it. Portable electric spas sit under the state appliance rules instead. And a permanent spa gets its own exception on a lot whose Solar Access Roof Area is too small for solar, and that definition is strict enough that a shaded lot can qualify where an open sunny one cannot.

How Big Does the Heat Pump Have to Be?

The sizing appendix says size it from the manufacturer’s own specifications, and hands you an equation for when the manufacturer publishes none. That equation takes your pool volume, the temperature rise you need, and the hours you get to do it in. Then it caps the rise at 10 degrees Fahrenheit and the time at 17.5 hours. Both ceilings are fixed, so the whole thing collapses into a floor: roughly 4.76 Btu per hour per gallon of water. Worth seeing in gallons before anybody picks a unit off a price sheet.

Scale surprises people. A 40 by 20 foot pool averaging five and a half feet deep holds close to 33,000 gallons, which puts its floor near 157,000 Btu per hour. That is a serious piece of equipment. It wants a pad sized for it and an electrical feed designed for it, which is why pool size and heating pathway get settled in the same conversation.

Do I Really Have to Have a Cover?

Yes. An outdoor pool or spa that gets electric or gas heating equipment gets a cover with it, and no exception is written against that rule. A heat pump counts as electric, so choosing one does not buy you out. The rule names only electric and gas equipment, though, and the code treats solar as a heating energy source of its own, so two pools sit outside it: one that finishes with no heating equipment at all, and one heated solely by a solar system.

On a new build that is barely an imposition, because the housing for an automatic cover gets formed into the bond beam and coping while the shell is going in. Cutting a recessed vault into a finished deck later is a much bigger job. Your cover also settles the coping profile, the deck layout, and where the motor lives. Easiest to see the options in person, at our showroom.

What Changes in the Plumbing and at the Equipment Pad?

Four things, all of them cheap while the trench is still open.

The code wants 18 inches of pipe between filter and heater, so a solar loop can be tied in later without reopening the plumbing. Dedicated suction and return lines satisfy it instead, and so do built-in connections. That dimension was 36 inches under the 2022 code, so a drawing still calling for 36 belongs to the last cycle.

Velocity gets capped at 6 feet per second through suction lines and 8 feet per second through returns, measured at maximum auxiliary flow. That makes it a pipe diameter decision, and it is driven by the spa spillover, the sheer descents and the deck jets rather than by filtration. Routine work now, expensive work later. It is a big part of what gets nailed down during design, engineering and planning.

Filtration flow gets a ceiling too: whatever turns the pool over in six hours, or 36 gallons per minute, whichever is greater. About 56 gallons per minute on a 20,000 gallon pool. The filter has to meet the NSF/ANSI 50 size for public pools, which on a house means a bigger filter than the pump alone would suggest. Big filter, low pump speed. That is where the code is pushing, and it is also how an equipment pad gets quiet, which is the part you actually notice.

Then controls, and one piece of misinformation worth killing. The only scheduling control the energy code asks for is a permanently installed time switch, settable so the pumps run inside off-peak windows, and the same rule wants directional inlets that mix the water. Staging is a separate requirement: where a heat pump runs with a supplementary heater, the controls have to keep the supplementary heater off whenever the heat pump can carry the load on its own. If a supplier tells you the Energy Code now requires a grid-responsive controller on your pool, it does not. The energy code does carry demand-responsive control requirements elsewhere, but they do not reach pool equipment. Demand response for pool equipment lives in Title 20, a separate set of rules with its own dates.

What This Means When We Design Your Pool

Three decisions move earlier than they used to. Heating pathway before the plumbing is laid out, because solar needs collector area and a loop while a heat pump needs electrical capacity at the pad. The cover before the coping and deck details are drawn. And pump, filter and pipe diameters sized against the auxiliary flow of every water feature on the plan, not against the pool’s volume alone.

Compliant heating equipment costs real money, and that money is far easier to carry when it sits in the number from the first meeting instead of turning up at plan check. It is one reason we keep pool financing on the site, and one reason our process opens with a designer rather than a bid. Follow it from the first design meeting through construction, look through our completed pool projects, or read up on the best time of year to build in the Bay Area. For a pool anywhere in our Bay Area service areas, ask us and we will come walk the lot.

For the Permit Desk: Where Each Requirement Lives

Nobody needs this to plan a pool. Your plan checker might, so it is down here.

Sections above are Title 24, Part 6 in its 2025 edition, with the Reference Joint Appendices adopted alongside it. The text sits on the Energy Commission’s 2025 Building Energy Efficiency Standards page.