MEP Plans in Westminster, CA
Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes in Westminster, prepared for plan check at the City of Westminster building department, with Title 24 available in the same order.
Westminster project facts we design around
| County | Orange County |
|---|---|
| Title 24 climate zone | Climate Zone 6, confirmed by ZIP for every project |
| Electric utility (most addresses) | Southern California Edison (SCE) |
| Permit review | The City of Westminster building department |
| ADU permits issued, 2021–2025 | 908 (#24 of 450 cities) |
| ADU approval timeline | Approve or deny within 60 days of a complete application (state law) |
ADU building activity in Westminster
Westminster issued 908 ADU building permits from 2021 through 2025, the 24th most among the 450 California cities that reported ADU permits. Permits went from 118 in 2021 to 215 in 2025.
| 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|
| 118 | 177 | 189 | 209 | 215 |
Source: California Department of Housing and Community Development, Annual Progress Report data (ADU building permits by year).
Title 24 in Climate Zone 6
- Windows: U-factor 0.30 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%).
- Solar PV sized by the CEC formula kW = (floor area x 0.594) / 1000 + 1.23; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 960 sq ft or smaller.
Climate Zone 6 requirements in full →
HVAC design for Westminster
The California Energy Commission's design-day data for Westminster gives the outdoor conditions a Manual J load calculation uses: a summer design temperature of 86°F and a winter design temperature of 33°F.
| Summer design (1%) | 86°F dry bulb / 68°F wet bulb |
|---|---|
| Winter design (median of extremes) | 33°F |
| Daily temperature range | 23°F |
| Elevation | 38 ft |
Loads are small in this mild climate, so the common mistake is oversizing. A right-sized heat pump runs longer, quieter cycles and controls humidity better than a rule-of-thumb unit.
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.
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
| Place | Climate zone | Electric utility | ADU permits 2021–25 |
|---|---|---|---|
| Fullerton | CZ 8 | Southern California Edison (SCE) | 2,171 |
| Garden Grove | CZ 8, 6 | Southern California Edison (SCE) | 2,046 |
| Anaheim | CZ 8 | Anaheim Public Utilities | 1,713 |
| Santa Ana | CZ 8 | Southern California Edison (SCE) | 956 |
| Huntington Beach | CZ 6 | Southern California Edison (SCE) | 437 |
| Laguna Beach | CZ 6 | Southern California Edison (SCE) | 432 |
Guides for Westminster projects
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Start My OrderGeneral guidance, not legal advice. Climate zone and utility are shown for most addresses in Westminster; requirements vary by project. Confirm with the City of Westminster building department.