Whether a new off-grid home can legally get its own water in California: the state well and water-rights rules, then the 45 counties where a specific groundwater basin adds a catch — each cited to the state water agency.
California water rules
Household well
Permit required — restricted
California requires no STATE permit for a domestic well — wells are permitted by the county — but under SGMA a Groundwater Sustainability Agency can meter or restrict new wells in medium/high-priority and critically overdrafted basins, and Executive Order N-7-22 requires counties in those basins to get GSA verification that a new well is consistent with the Groundwater Sustainability Plan before permitting.
Limit: 2 acre-feet/year de minimis under SGMA (Water Code §10721(e)) — largely exempt from GSA metering/fees
Actively managedAlameda CountyNiles Cone & Livermore Valley Basins — Medium Priority15
Actively managedButte CountySacramento Valley high-priority subbasins34
Actively managedColusa CountySacramento Valley high-priority subbasins36
Actively managedContra Costa CountyEast Contra Costa Subbasin — Medium Priority14
Actively managedGlenn CountySacramento Valley high-priority subbasins40
Actively managedHumboldt CountyEel River Valley Basin — Medium Priority51
Actively managedLake CountyBig Valley Basin (5-015, Lake County) — Medium Priority39
Actively managedLassen CountyBig Valley Basin (5-004, Lassen-Modoc) — Medium Priority45
Actively managedMendocino CountyUkiah Valley Basin — Medium Priority48
Actively managedModoc CountyTulelake Subbasin — Medium Priority46
Actively managedNapa CountyNapa Valley & Sonoma Valley Subbasins — High Priority28
Actively managedOrange CountyCoastal Plain of Orange County Basin — Medium Priority13
Actively managedPlacer CountySacramento Valley high-priority subbasins40
Actively managedPlumas CountySierra Valley Basin — Medium Priority45
Actively managedSacramento CountySacramento Valley high-priority subbasins19
Actively managedSanta Clara CountySanta Clara & Llagas Area Subbasins — High Priority17
Actively managedShasta CountyRedding Area Subbasins (Anderson, Enterprise) — Medium Priority46
Actively managedSierra CountySierra Valley Basin — Medium Priority44
Actively managedSolano CountySacramento Valley high-priority subbasins20
Actively managedSonoma CountyNapa Valley & Sonoma Valley Subbasins — High Priority27
Actively managedSutter CountySacramento Valley high-priority subbasins34
Actively managedTehama CountySacramento Valley high-priority subbasins41
Actively managedYolo CountySacramento Valley high-priority subbasins28
Actively managedYuba CountySacramento Valley high-priority subbasins40
The Bolthole Index Letter
One email a week: the best counties to live off-grid, rule changes that matter, and California water-rule changes as basins close. No spam, unsubscribe anytime.
General guidance, not legal advice. Off-grid, building, and land-use rules are often set at the county level and change often. Verify with your county and state before acting. Data reviewed 2026-06-26.