MEP Plans in Los Altos Hills, CA
Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes in Los Altos Hills, prepared for plan check at the City of Los Altos Hills building department, with Title 24 available in the same order.
Los Altos Hills project facts we design around
| County | Santa Clara County |
|---|---|
| Title 24 climate zone | Climate Zone 4, confirmed by ZIP for every project |
| Electric utility (most addresses) | Pacific Gas and Electric (PG&E) |
| Permit review | The City of Los Altos Hills building department |
| ADU permits issued, 2021–2025 | 277 (#104 of 450 cities) |
| ADU approval timeline | Approve or deny within 60 days of a complete application (state law) |
ADU building activity in Los Altos Hills
Los Altos Hills issued 277 ADU building permits from 2021 through 2025, the 104th most among the 450 California cities that reported ADU permits. Permits went from 79 in 2021 to 30 in 2025.
| 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|
| 79 | 110 | 23 | 35 | 30 |
Source: California Department of Housing and Community Development, Annual Progress Report data (ADU building permits by year).
Title 24 in Climate Zone 4
- 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%).
- Solar PV sized by the CEC formula kW = (floor area x 0.586) / 1000 + 1.21; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 1,007 sq ft or smaller.
Climate Zone 4 requirements in full →
HVAC design for Los Altos Hills
The California Energy Commission's design-day data for Los Altos Hills gives the outdoor conditions a Manual J load calculation uses: a summer design temperature of 83°F and a winter design temperature of 28°F.
| Summer design (1%) | 83°F dry bulb / 64°F wet bulb |
|---|---|
| Winter design (median of extremes) | 28°F |
| Daily temperature range | 25°F |
| Elevation | 183 ft |
| Heating degree days | 1,103 |
Both seasons matter here. The heat pump is usually sized for the 83°F cooling condition and then checked to confirm it still covers the heating load at 28°F.
Electrical service from Pacific Gas and Electric (PG&E)
If the load calculation shows you need a service upgrade, a second meter or a relocated service, Pacific Gas and Electric (PG&E) handles that through its Your Projects portal, separately from the building permit.
ADU electrical service with Pacific Gas and Electric (PG&E) →
Plumbing and sewer
The plumbing plan shows the route, slope and cleanouts of the connection to the existing sewer lateral. Some Bay Area cities also have private sewer lateral inspection rules, so ask whether your project triggers one.
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 |
|---|---|---|---|
| San Jose | CZ 4 | Pacific Gas and Electric (PG&E) | 2,399 |
| Campbell | CZ 4 | Pacific Gas and Electric (PG&E) | 1,097 |
| Palo Alto | CZ 4 | City of Palo Alto Utilities | 723 |
| Los Gatos | CZ 4 | Pacific Gas and Electric (PG&E) | 450 |
| Saratoga | CZ 4 | Pacific Gas and Electric (PG&E) | 387 |
| Los Altos | CZ 4 | Pacific Gas and Electric (PG&E) | 384 |
Santa Clara County → · All California cities and communities →
Guides for Los Altos Hills projects
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Start My OrderGeneral guidance, not legal advice. Climate zone and utility are shown for most addresses in Los Altos Hills; requirements vary by project. Confirm with the City of Los Altos Hills building department.