MEP Plans in Graton, CA

Graton project facts we design around

County	Sonoma County (unincorporated)
Title 24 climate zone	Climate Zone 2, confirmed by ZIP for every project
Electric utility (most addresses)	Pacific Gas and Electric (PG&E)
Permits issued by	Permit Sonoma
ADU permits issued, 2021–2025	5
ADU approval timeline	Approve or deny within 60 days of a complete application (state law)

ADU building activity in Graton

Sonoma County issued 5 ADU building permits from 2021 through 2025 for addresses in Graton, based on the county's reports to the state. Permits went from 1 in 2021 to 2 in 2024.

2021	2022	2023	2024	2025
1	1	1	2	not reported

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

Title 24 in Climate Zone 2

• 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 0.621) / 1000 + 1.22; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 934 sq ft or smaller.

Climate Zone 2 requirements in full →

HVAC design for Graton

The California Energy Commission's design-day data for Graton gives the outdoor conditions a Manual J load calculation uses: a summer design temperature of 88°F and a winter design temperature of 22°F.

Summer design (1%)	88°F dry bulb / 66°F wet bulb
Winter design (median of extremes)	22°F
Daily temperature range	34°F
Elevation	200 ft
Heating degree days	3,409

Both seasons matter here. The heat pump is usually sized for the 88°F cooling condition and then checked to confirm it still covers the heating load at 22°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 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.