Off-grid site report
Honolulu County, HI
21.2751, -157.8154 · 20 ft elevationRead this before you act on anything below. This is my researched starting point for Honolulu County, HI, 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 rulesHonolulu County, HI
Zoning & raw-land occupancy
Varies locallyAll of Oahu falls under the City and County of Honolulu's Land Use Ordinance (Chapter 21, ROH), administered by the Department of Planning and Permitting, with districts ranging from residential to agricultural and conservation. The Council is actively revising this ordinance (Bill 64/Bill 10), so what's allowed on a given parcel can shift, and you should check current district rules with DPP before making plans. source
Dwellings, tiny homes & RVs
Unclear - verifyI couldn't find an official Honolulu source spelling out rules for living long-term in an RV or tiny home outside a permitted dwelling unit. The Land Use Ordinance defines dwelling units (including farm dwellings, ohana units, and accessory dwellings), but permanent occupancy of an RV or similar structure isn't addressed on any DPP page I found, so confirm directly with DPP before relying on one as a residence. source
Building permits & codes
RestrictedBuilding permits are required countywide and administered by the Department of Planning and Permitting, which acts as Oahu's central coordinating agency for zoning and construction compliance. I did not find official fee or timeline figures, so check those specifics with DPP directly. source
Septic & composting toilets
Generally allowedThe state Department of Health, not a separate Honolulu ordinance, regulates individual wastewater systems islandwide, including septic tanks, aerobic units, and composting or incinerator toilets. A new system needs a Hawaii-licensed engineer's design and DOH approval, and composting toilets still require a separate approved path for shower and kitchen greywater. source
Greywater reuse
Generally allowedGreywater reuse is governed at the state level by DOH under HRS 342D-70 and HAR Title 11, Chapter 62; I found no distinct Honolulu County greywater ordinance, so the county layers its own permit and inspection steps on top of the state standard. Composting-toilet setups still need a DOH-approved greywater disposal method for water that isn't toilet waste. source
Rainwater harvesting
Generally allowedRainwater catchment is allowed under the state mandate requiring counties to permit it, and I found no Honolulu-specific restriction on top of that in this research pass. The DPP and the Board of Water Supply oversee related plumbing cross-connection rules, but that's separate from banning catchment itself.
Private wells & water rights
RestrictedPrivate wells are permitted but go through two layers of review on Oahu: the state Commission on Water Resource Management issues well construction and pump installation permits, and the Honolulu Board of Water Supply separately reviews construction plans and charges its own well permit fee plus a bond requirement. Sequencing matters here, CWRM advises applicants to sort out any required Water Use Permit before drilling permits are issued, so start with CWRM and loop in BWS. source
Living disconnected from utilities
Unclear - verifyThere's no standalone Honolulu ordinance banning off-grid living, but going fully disconnected is practically harder here because of comprehensive countywide zoning and an active DOH/DPP compliance framework for wastewater and building. Legality ends up being assembled piece by piece from LUO zoning rules, DPP building permits, DOH's wastewater approval process, and, if you're drilling a well, both CWRM and the Board of Water Supply, so confirm your specific zoning district and plans with DPP first.
Sun30-year normals
- Peak-sun hours, annual average
- 5.7 hrs/day
- Worst month (sizes an off-grid array)
- 4.7 hrs/day
- Yearly output per 1 kW of panels
- 1,594 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 22 in/yr
- Snowfall
- 0 in/yr
- Heating degree days
- 0 (moderate)
How far help isstraight-line
- Hospital
Kapi'olani Medical Center for Women and Children - 2.1 mi
- Fire station
Kaimuki Fire Station - 1.1 mi
- Hardware store
City Mill - 1.0 mi
- Grocery
Safeway - 0.6 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 96815).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Honolulu County, HI?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.