Off-grid site report
Marin County, CA
38.0061, -122.5381 · 112 ft elevationRead this before you act on anything below. This is my researched starting point for Marin County, CA, not legal advice and not a guarantee. Rules change, and the deciding facts on any specific parcel (setbacks, perc results, overlay districts, deed restrictions, road frontage) live at the county or town office, not in any database. Before you buy land or build, confirm the current rules directly with the local zoning and health offices - the sources on this page tell you exactly who to call.
The local rulesMarin County, CA
Zoning & raw-land occupancy
RestrictedMarin County's Title 22 Development Code sets allowed land uses by zoning district for unincorporated areas, with Title 20 governing the Coastal Zone; there's no countywide allowance for informal occupancy of raw land, and 22 Community/Area Plans add local policy layers. Incorporated towns have their own separate zoning codes. source
Dwellings, tiny homes & RVs
RestrictedWhether a tiny home or RV is legal depends on state HCD classification, and Marin's ADU guidance suggests RVs, tiny homes on wheels, and yurts usually aren't treated as ADUs. Long-term RV occupancy of vacant land without a primary dwelling isn't confirmed as authorized in any official Marin source, so treat it as prohibited absent a specific permit.
Building permits & codes
RestrictedMarin County CDA issues building permits under the state-mandated Title 24 code, with some streamlined process for septic-served properties, and Coastal Zone parcels may need a Coastal Permit Exclusion before building, septic, or well permits are issued. source
Septic & composting toilets
RestrictedMarin County Environmental Health Services permits septic (OWTS) systems under a state-required Local Agency Management Program that is still being finalized, and applies stricter siting/design standards than the state baseline in parts of the county due to topography. Composting toilets aren't separately addressed in official sources, so confirm with EHS. source
Greywater reuse
Generally allowedNo Marin County-specific greywater ordinance beyond the state Plumbing Code was found; this appears to follow the state baseline, but it's not confirmed via an official Marin-specific page.
Rainwater harvesting
Generally allowedNo Marin County ordinance restricting rooftop rainwater harvesting was found; this appears to follow the state baseline (Water Code, AB 1750) without added county rules, though this isn't confirmed by an official Marin-specific source.
Private wells & water rights
RestrictedMarin County Environmental Health Services issues well construction and operation permits under County Code Chapter 7.28, requires state drinking-water quality testing, and adds extra requirements in the Coastal Zone, on the Bolinas Gridded Mesa, or within water district service areas like Marin Municipal Water District. source
Living disconnected from utilities
Unclear - verifyNo dedicated Marin County ordinance directly addresses off-grid utility disconnection; it's governed indirectly through required building, septic, and well permits for any habitable dwelling. Whether any habitability rule requires grid electrical connection is not confirmed in official sources, so ask CDA directly.
Sun30-year normals
- Peak-sun hours, annual average
- 5.8 hrs/day
- Worst month (sizes an off-grid array)
- 3.6 hrs/day
- Yearly output per 1 kW of panels
- 1,633 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 48 in/yr
- Snowfall
- 0 in/yr
- Heating degree days
- 2,714 (mild)
- Frost-free season
- Jan 26 to Dec 21
How far help isstraight-line
- Hospital
- none within range
- Fire station
Ross Valley Fire District (Station 20) - 2.3 mi
- Hardware store
Fairfax Lumber and Hardware - 3.2 mi
- Grocery
United Market - 2.2 mi
From OpenStreetMap. Road miles will be longer, often much longer in hill country.
Plan this spot
These open with this location's real numbers already filled in (ZIP 94912).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Marin County, CA?The rules above are the jurisdiction. The land check runs the parcel itself: flood zone, soils and septic suitability, wetlands, slope, access, climate, and these verdicts, from a parcel number or coordinates.
Check a parcel →Share or save this report:New report
Sources: US Census Bureau geocoder; NLR PVWatts v8 (solar); NOAA NCEI 1991-2020 climate normals (nearest station) or Open-Meteo (ZIP-centroid) for weather; Open-Elevation; OpenStreetMap contributors. Public data retrieved Aug 22, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.
New here, or not sure where this fits? Start here walks through the whole thing in order.