MEP Plans in Arcata, CA
Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes in Arcata, prepared for plan check at the City of Arcata building department, with Title 24 available in the same order.
Arcata project facts we design around
| County | Humboldt County |
|---|---|
| Title 24 climate zone | Climate Zone 1, confirmed by ZIP for every project |
| Electric utility (most addresses) | Pacific Gas and Electric (PG&E) |
| Permit review | The City of Arcata building department |
| ADU permits issued, 2021–2025 | 74 (#260 of 450 cities) |
| ADU approval timeline | Approve or deny within 60 days of a complete application (state law) |
ADU building activity in Arcata
Arcata issued 74 ADU building permits from 2021 through 2025, the 260th most among the 450 California cities that reported ADU permits. Permits went from 9 in 2021 to 10 in 2025.
| 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|
| 9 | 17 | 19 | 19 | 10 |
Source: California Department of Housing and Community Development, Annual Progress Report data (ADU building permits by year).
Title 24 in Climate Zone 1
- Windows: U-factor 0.27 or lower (no SHGC limit in this zone), with total window area up to 20% of floor area.
- Solar PV sized by the CEC formula kW = (floor area x 0.793) / 1000 + 1.27; no PV is required if that is under 1.8 kWdc, which for a single ADU works out to about 668 sq ft or smaller.
Climate Zone 1 requirements in full →
HVAC design for Arcata
The California Energy Commission's design-day data for Arcata gives the outdoor conditions a Manual J load calculation uses: a summer design temperature of 68°F and a winter design temperature of 28°F.
| Summer design (1%) | 68°F dry bulb / 59°F wet bulb |
|---|---|
| Winter design (median of extremes) | 28°F |
| Daily temperature range | 11°F |
| Elevation | 218 ft |
| Heating degree days | 5,029 |
Both seasons matter here. The heat pump is usually sized for the 68°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.
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 |
|---|---|---|---|
| Eureka | CZ 1 | Pacific Gas and Electric (PG&E) | 166 |
| McKinleyville (unincorp.) | CZ 1 | Pacific Gas and Electric (PG&E) | 40 |
| Fortuna | CZ 1 | Pacific Gas and Electric (PG&E) | 17 |
| Ferndale | CZ 1 | Pacific Gas and Electric (PG&E) | 13 |
| Blue Lake | CZ 1 | Pacific Gas and Electric (PG&E) | 6 |
| Rio Dell | CZ 1 | Pacific Gas and Electric (PG&E) | 5 |
Guides for Arcata projects
Ready for permit-ready MEP plans in Arcata?
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 Arcata; requirements vary by project. Confirm with the City of Arcata building department.