Off-grid site report
Rock County, WI
42.6281, -89.1037 · 817 ft elevationRead this before you act on anything below. This is my researched starting point for Rock County, WI, 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 rulesRock County, WI
Zoning & raw-land occupancy
Varies locallyRock County has no countywide general zoning; towns hold zoning authority and rules vary town by town. The county only handles shoreland, floodplain, airport overlay, land division, and address ordinances directly. source
Dwellings, tiny homes & RVs
Varies locallySingle- and two-family construction falls under the Wisconsin Uniform Dwelling Code, but each town in Rock County adopts and enforces it locally (for example, the Town of Lima adopts SPS 320-325 with its own Building Inspector). No countywide rule on tiny homes or RVs as permanent dwellings was found, so check with your specific town. source
Building permits & codes
Generally allowedBuilding permits in unincorporated Rock County are issued by the Town, City, or Village under the state Uniform Dwelling Code, not by the county. The county's own erosion control permit is separate and only applies to larger land-disturbing projects, exempting UDC-covered single/two-family construction. source
Septic & composting toilets
RestrictedRock County Public Health reviews plans, issues permits, and inspects POWTS (septic) installations, and runs a maintenance program requiring inspection and periodic pumping. Sanitary permits are time-limited and must be renewed. Composting toilet rules specifically were not confirmed but likely fall under this same county POWTS framework, so ask Rock County Public Health. source
Greywater reuse
Unclear - verifyNo Rock County ordinance or Public Health page specifically addressing greywater reuse separate from septic/POWTS was found; this is not confirmed at the county level, so ask Rock County Public Health whether it falls under the general POWTS permitting framework or the state plumbing code baseline.
Rainwater harvesting
Unclear - verifyNo Rock County ordinance addressing rainwater harvesting was found in the research; this is not confirmed at the county level, so treat it as governed by the state baseline until you confirm otherwise with your town or the county.
Private wells & water rights
Unclear - verifyNo dedicated Rock County well-permitting office or page was found; domestic wells are generally governed by the Wisconsin DNR's well code, but it's not confirmed whether Rock County Public Health handles local administration, so ask both the county and DNR. source
Living disconnected from utilities
Unclear - verifyNo Rock County ordinance or state statute was found addressing full disconnection of a legal dwelling from electric, gas, or municipal utility service; this remains not confirmed, so ask your town's zoning/building office directly.
Sun30-year normals
- Peak-sun hours, annual average
- 4.6 hrs/day
- Worst month (sizes an off-grid array)
- 3.0 hrs/day
- Yearly output per 1 kW of panels
- 1,355 kWh
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Weather1991-2020
- Precipitation
- 35 in/yr
- Snowfall
- 35 in/yr
- Heating degree days
- 7,038 (cold)
- Frost-free season
- Apr 26 to Oct 9
How far help isstraight-line
- Hospital
Mercy Health Hospital & Trauma Center - 5.5 mi
- Fire station
Janesville Fire Station #2 - 4.1 mi
- Hardware store
Harris Ace Hardware - 7.6 mi
- Grocery
Mexican Market - 7.1 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 53501).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Rock County, WI?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.