Off-grid site report
Knox County, IL
40.9186, -90.4102 · 764 ft elevationRead this before you act on anything below. This is my researched starting point for Knox County, IL, 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 rulesKnox County, IL
Zoning & raw-land occupancy
Varies locallyUnincorporated Knox County follows a countywide zoning resolution with seven districts, administered by Knox County Zoning. The City of Galesburg enforces its own ordinance within city limits and a 1.5-mile extraterritorial radius, and other towns may have their own rules too. source
Dwellings, tiny homes & RVs
Unclear - verifyThe county resolution recognizes manufactured/mobile homes as a dwelling category, but no official minimum size or RV/tiny-home occupancy rule was found. Confirm with Knox County Zoning. source
Building permits & codes
RestrictedKnox County has adopted International Codes for residential and commercial construction and issues county building permits through the Zoning Department; a new 2025 statewide code baseline also applies. source
Septic & composting toilets
Generally allowedThe Knox County Health Department's Environmental Health division issues onsite wastewater disposal permits under county ordinance and the state Private Sewage Disposal Code; composting toilets would need review as an alternative system. source
Greywater reuse
Unclear - verifyNo Knox County or Illinois document specifically addresses residential greywater reuse; ask the Knox County Health Department Environmental Health division if it comes up during a septic permit review.
Rainwater harvesting
Unclear - verifyNo county or state document was found specifically permitting or restricting residential rainwater harvesting in Knox County.
Private wells & water rights
Generally allowedThe Knox County Health Department issues well construction, modification, and sealing permits under the statewide Illinois Water Well Construction Code, with IDPH as backstop authority. source
Living disconnected from utilities
Unclear - verifyNo ordinance was found prohibiting full grid disconnection, but septic and well permits are still required regardless, and building/property maintenance codes may factor into habitability. Confirm with Knox County Zoning and Health Department.
Sun30-year normals
- Peak-sun hours, annual average
- 4.8 hrs/day
- Worst month (sizes an off-grid array)
- 3.2 hrs/day
- Yearly output per 1 kW of panels
- 1,387 kWh
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Weather1991-2020
- Precipitation
- 38 in/yr
- Snowfall
- 23 in/yr
- Heating degree days
- 6,390 (cold)
- Frost-free season
- Apr 21 to Oct 14
How far help isstraight-line
- Hospital
OSF Saint Mary Medical Center - 5.4 mi
- Fire station
Galesburg Central Fire Station - 2.8 mi
- Hardware store
Harbor Freight Tools - 4.1 mi
- Grocery
Hi-Lo Supermarket - 2.7 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 61402).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Knox County, IL?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.