Off-grid site report
Fairfax County, VA
38.9353, -77.1769 · 289 ft elevationRead this before you act on anything below. This is my researched starting point for Fairfax County, VA, 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 rulesFairfax County, VA
Zoning & raw-land occupancy
RestrictedFairfax County has countywide zoning with no unzoned rural pockets, and the Zoning Ordinance generally caps you at one dwelling unit per lot regardless of size, with limited exceptions. Living on raw land without an approved dwelling isn't specifically addressed, so I'd call that unconfirmed and worth a call to the county's Zoning Administration Division. source
Dwellings, tiny homes & RVs
RestrictedThe county's code compliance guidance confirms you can park an RV on residential property, but that's about storage, not living in it full-time as your home. I couldn't find any Fairfax County page that affirmatively allows year-round RV or tiny-house-on-wheels residency outside a licensed campground, so treat this as restricted until you confirm otherwise with Code Compliance or Zoning. source
Building permits & codes
Generally allowedFairfax County administers Virginia's statewide building code locally through Land Development Services and the Zoning Permits office, so any structure you build will need to go through their standard permitting and inspection process. source
Septic & composting toilets
Generally allowedThe county Health Department administers septic systems, alternative onsite systems, and composting or incinerating toilets under its Sewage Handling and Disposal Regulations (County Code Chapter 68.1), which layers extra local rules, like mandatory pump-outs at least every five years, on top of the state framework. Applications need to go through a licensed Onsite Soil Evaluator. source
Greywater reuse
Unclear - verifyI couldn't find a Fairfax County specific greywater ordinance; the state framework itself is unsettled, with Virginia's graywater regulations described as pending and its Water Reclamation and Reuse Regulations actually excluding greywater. Best move is to ask the county Health Department's Division of Environmental Health directly before setting up a greywater system. source
Rainwater harvesting
Generally allowedFairfax County's Public Works department actively promotes rainwater harvesting as a stormwater best-management practice and has design standards for it in the county's Public Facilities Manual, with the state layering additional tiered regulations (and even protecting larger Tier 4 system owners from being forced to hook up to municipal water). Check with Public Works Stormwater Planning for sizing and design requirements. source
Private wells & water rights
Generally allowedFairfax County has its own Private Well Water Ordinance (Chapter 70.1) layered on top of the state VDH rules, and the Health Department issues well construction permits after review, with applications submitted by a licensed Onsite Soil Evaluator. source
Living disconnected from utilities
Unclear - verifyI didn't find any Fairfax County zoning, building, or health page that explicitly requires connecting to public electric service to occupy a home, so going off-grid on power specifically doesn't appear to be banned outright. That said, occupancy still practically depends on having an approved water source and sewage system under the septic and well ordinances, so confirm the full picture with Land Development Services before you plan on a fully disconnected setup.
Sun30-year normals
- Peak-sun hours, annual average
- 4.8 hrs/day
- Worst month (sizes an off-grid array)
- 3.4 hrs/day
- Yearly output per 1 kW of panels
- 1,384 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 46 in/yr
- Heating degree days
- 4,398 (moderate)
- Frost-free season
- Apr 12 to Oct 29
How far help isstraight-line
- Hospital
- none within range
- Fire station
Naval Surface Warfare Center Fire Station - 3.1 mi
- Hardware store
Glen Echo Hardware - 3.1 mi
- Grocery
Giant - 4.8 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 22106).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Fairfax County, VA?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.