MEP Plans in Modesto, CA
Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes in Modesto, prepared for plan check at the City of Modesto building department, with Title 24 available in the same order.
Modesto project facts we design around
| County | Stanislaus County |
|---|---|
| Title 24 climate zone | Climate Zone 12, confirmed by ZIP for every project |
| Electric utility (most addresses) | Modesto Irrigation District (MID) |
| Permit review | The City of Modesto building department |
| ADU permits issued, 2021–2025 | 527 (#38 of 450 cities) |
| ADU approval timeline | Approve or deny within 60 days of a complete application (state law) |
ADU building activity in Modesto
Modesto issued 527 ADU building permits from 2021 through 2025, the 38th most among the 450 California cities that reported ADU permits. Permits went from 7 in 2021 to 198 in 2025.
| 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|
| 7 | 78 | 132 | 112 | 198 |
Source: California Department of Housing and Community Development, Annual Progress Report data (ADU building permits by year).
Title 24 in Climate Zone 12
- 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 0.613) / 1000 + 1.4; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 653 sq ft or smaller.
Climate Zone 12 requirements in full →
HVAC design for Modesto
The California Energy Commission's design-day data for Modesto gives the outdoor conditions a Manual J load calculation uses: a summer design temperature of 98°F and a winter design temperature of 25°F.
| Summer design (1%) | 98°F dry bulb / 70°F wet bulb |
|---|---|
| Winter design (median of extremes) | 25°F |
| Daily temperature range | 36°F |
| Elevation | 91 ft |
| Heating degree days | 2,671 |
Both seasons matter here. The heat pump is usually sized for the 98°F cooling condition and then checked to confirm it still covers the heating load at 25°F.
Electrical service from Modesto Irrigation District (MID)
If the load calculation shows you need a service upgrade, a second meter or a relocated service, Modesto Irrigation District (MID) handles that through its Design Project Request process, separately from the building permit.
ADU electrical service with Modesto Irrigation District (MID) →
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 |
|---|---|---|---|
| Ceres | CZ 12 | Turlock Irrigation District (TID) | 42 |
| Turlock | CZ 12 | Turlock Irrigation District (TID) | 26 |
| Keyes (unincorp.) | CZ 12 | Turlock Irrigation District (TID) | 25 |
| Waterford | CZ 12 | Modesto Irrigation District (MID) | 23 |
| Salida (unincorp.) | CZ 12 | Modesto Irrigation District (MID) | 23 |
| Newman | CZ 12 | Pacific Gas and Electric (PG&E) | 21 |
Stanislaus County → · All California cities and communities →
Guides for Modesto projects
Ready for permit-ready MEP plans in Modesto?
Upload your architectural plans, get an instant flat price, and receive PDF plans in about 5 business days.
Start My OrderGeneral guidance, not legal advice. Climate zone and utility are shown for most addresses in Modesto; requirements vary by project. Confirm with the City of Modesto building department.