MEP Plans in Mountain View, CA

Mountain View 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 Mountain View building department
ADU permits issued, 2021–2025	317 (#89 of 450 cities)
ADU approval timeline	Approve or deny within 60 days of a complete application (state law)

ADU building activity in Mountain View

Mountain View issued 317 ADU building permits from 2021 through 2025, the 89th most among the 450 California cities that reported ADU permits. Permits went from 31 in 2021 to 86 in 2025.

2021	2022	2023	2024	2025
31	42	101	57	86

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 Mountain View

The California Energy Commission's design-day data for Mountain View 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	95 ft

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.