Title 24 Reports in Rancho Cucamonga

All four of Rancho Cucamonga's street ZIP codes are climate zone 10, Alta Loma and Etiwanda included. What does vary inside the city is who supplies the power, and whether a lot sits in the fire hazard zone along its northern edge.

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A utility that pays for margin

Southern California Edison serves most of Rancho Cucamonga, but not all of it. The City set up its own electric utility, the Rancho Cucamonga Municipal Utility, in 2001, and it began serving customers in May 2004. Its territory is the Victoria Gardens shopping centre with the shops, offices and housing built around it in the southeast of the city, more than 3,900 metered accounts in all.

Inside that territory, RCMU lists an incentive for new development built to beat Title 24 by 15% or more. Its guidelines, last issued in 2018, scale the payment to the margin shown in the final compliance run, with a CF1R for each plan type, and leave remodels and additions out. A compliance margin is normally just the distance between pass and fail. Here it can be worth something, so a builder in the RCMU area does well to decide before the model is built whether the design is aiming at the minimum or at a margin.

Alta Loma and Etiwanda meet the foothills

Alta Loma, Cucamonga and Etiwanda are the three communities the city was formed from. The City describes its northern boundary as a wildland-urban interface where the Alta Loma and Etiwanda neighbourhoods meet the San Gabriel foothills, in the Very High Fire Hazard Severity Zone. The Rancho Cucamonga Fire Protection District, a subsidiary district of the City, adopted Ordinance FD60 on 19 November 2025, designating the State Fire Marshal's hazard zones and establishing a Wildland-Urban Interface Fire Area from 1 January 2026. On a mapped lot the ignition-resistant rules come from the California Wildland-Urban Interface Code, Title 24 Part 7, and they reach the same windows and vents the energy report describes.

The climate zone does not follow the fire map uphill. The city stays zone 10 to the mountain front; Mount Baldy (91759), up in the range, is zone 16, the mountain zone.

Etiwanda Heights

Etiwanda Heights came into the city as about 4,085 acres annexed from San Bernardino County, after the county's Local Agency Formation Commission approved it on 9 November 2020. The plan conserves 3,603 acres and sets aside a 790-acre neighbourhood for 2,700 to 3,000 single-family homes, each a newly constructed building under the Energy Code with a solar system sized by it.

Uploading the energy calculations

The Building and Safety Services Department receives every plan submittal electronically through the Rancho Cucamonga Online Permit Center, and its submittal guide says paper plans are not accepted; T24 energy calculations are uploaded as a document of their own. The residential checklist asks for energy calculations per Title 24, with electrical plans showing the PV panel location those calculations require. Plans filed on or after 1 January 2026 are checked against the 2025 Energy Code. Ordinance 1048, the City's November 2025 code ordinance, adopts the other 2025 codes with local amendments but does not list the Energy Code, which applies as the state wrote it. Rooftop solar on a single-family home or duplex can go through SolarAPP+.

Common Title 24 Questions in Rancho Cucamonga

Rancho Cucamonga projects fall in California climate zone 10. The zone drives the envelope and equipment requirements a report has to meet, and a single city can span more than one, so it is confirmed per address.

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Title 24 in San Bernardino County