Unincorporated San Bernardino County · Climate Zone 14

MEP Plans in Phelan, CA

Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes in Phelan (unincorporated San Bernardino County), prepared for plan check at San Bernardino County Land Use Services – Building & Safety, with Title 24 available in the same order.

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Phelan project facts we design around

CountySan Bernardino County (unincorporated)
Title 24 climate zoneClimate Zone 14, confirmed by ZIP for every project
Electric utility (most addresses)Southern California Edison (SCE)
Permits issued bySan Bernardino County Land Use Services – Building & Safety
ADU permits issued, 2021–202516
ADU approval timelineApprove or deny within 60 days of a complete application (state law)

ADU building activity in Phelan

San Bernardino County issued 16 ADU building permits from 2021 through 2025 for addresses in Phelan, based on the county's reports to the state. Permits went from 5 in 2021 to 2 in 2025.

20212022202320242025
51not reported82

Source: California Department of Housing and Community Development, Annual Progress Report data (ADU building permits by year).

Title 24 in Climate Zone 14

  • Windows: U-factor 0.27 or lower and solar heat gain coefficient (SHGC) 0.23 or lower, with total window area up to 20% of floor area (west-facing up to 5%).
  • Whole-house fan required (at least 1.5 cfm per square foot of floor area); units of 500 sq ft or less are exempt.
  • Cool roof required: steep-sloped roofs need aged solar reflectance 0.2 or higher and thermal emittance 0.75 or higher.
  • Solar PV sized by the CEC formula kW = (floor area x 0.741) / 1000 + 1.26; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 729 sq ft or smaller.

Climate Zone 14 requirements in full →

HVAC design for Phelan

The HVAC is sized from a room-by-room Manual J using the outdoor design conditions for the address, in Climate Zone 14's high-desert / desert climate with extreme summer heat. Cooling capacity and equipment rated for high outdoor temperatures.

Electrical service from Southern California Edison (SCE)

If the load calculation shows you need a service upgrade, a second meter or a relocated service, Southern California Edison (SCE) handles that through its Building, Renovation, and Project Planning Portal, separately from the building permit.

ADU electrical service with Southern California Edison (SCE) →

Plumbing and sewer

The plumbing plan shows the route, slope and cleanouts of the connection to the existing sewer lateral or septic system.

Pricing is flat statewide: ADU plans from $995, full ADU MEP package from $2,295, Title 24 add-on $240. See what's in a complete ADU MEP set.

Nearby places compared

PlaceClimate zoneElectric utilityADU permits 2021–25
San BernardinoCZ 10, 16Southern California Edison (SCE)854
FontanaCZ 10Southern California Edison (SCE)754
OntarioCZ 10Southern California Edison (SCE)563
Rancho CucamongaCZ 10Southern California Edison (SCE)316
UplandCZ 10Southern California Edison (SCE)285
ChinoCZ 10Southern California Edison (SCE)269

San Bernardino County → · All California cities and communities →

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General guidance, not legal advice. Climate zone and utility are shown for most addresses in Phelan; requirements vary by project. Confirm with San Bernardino County Land Use Services – Building & Safety.