Off-grid site report
Mercer County, KY
37.7875, -84.8668 · 846 ft elevationRead this before you act on anything below. This is my researched starting point for Mercer County, KY, 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 rulesMercer County, KY
Zoning & raw-land occupancy
RestrictedMercer County has adopted countywide zoning jointly with Harrodsburg and Burgin through the Harrodsburg/Mercer County Joint Planning & Zoning Commission, so raw land use, setbacks, and placement are subject to local zoning review, not just state default rules. Anyone planning to live off-grid on raw land here should check in with the Joint Planning & Zoning Commission before buying or building. source
Dwellings, tiny homes & RVs
RestrictedTiny homes, RVs, and mobile homes are subject to review by the Joint Planning & Zoning Commission staff for setbacks, use, and placement before a building permit is issued. The exact local standards for tiny-home-on-foundation or RV siting were not confirmed in an official current Mercer County document, so I'd ask the Commission directly about your specific dwelling type. source
Building permits & codes
RestrictedMercer County enforces building permits and inspections locally through the County Building Inspector, housed with the Planning & Zoning office in Harrodsburg City Hall, including plan review and flood plain review before a permit is issued. This means Mercer is one of the Kentucky counties that has opted into local enforcement of the state residential code rather than skipping it. source
Septic & composting toilets
Generally allowedSeptic systems are allowed but require a permit from the Mercer County Health Department's Environmental Health Branch, including a soil evaluation and a Permit to Construct, and installation generally must be done by a Kentucky certified installer with a homeowner self-install exception under state rule. Composting toilets aren't separately addressed on the county site, so the state baseline under 902 KAR Chapter 10 would apply; confirm specifics with the Health Department. source
Greywater reuse
Generally allowedI didn't find a Mercer County-specific greywater ordinance, so this likely falls under the state baseline in 902 KAR 10:085, administered by the same Health Department environmental branch that handles septic permitting. Best to confirm any greywater reuse plans with that office directly since there's no dedicated county page on it. source
Rainwater harvesting
Generally allowedNo Mercer County ordinance restricting rainwater collection for non-potable use turned up in official sources, so this appears to follow the general state baseline of being allowed. This isn't specifically confirmed as different from that baseline, so treat it as a reasonably safe but unverified assumption.
Private wells & water rights
Generally allowedPrivate wells are permitted, and Kentucky requires construction, modification, or abandonment of wells to be handled by a state-certified well driller under KRS 223.425 and 401 KAR 6:320, a state-level rule rather than a Mercer County one. No separate county well permit was found, so the main authority here is the Kentucky Energy and Environment Cabinet, Division of Water. source
Living disconnected from utilities
Unclear - verifyI could not confirm any Mercer County ordinance that flatly requires connecting to grid electric or municipal water and sewer to live on your property. That said, the septic permitting process references issuance of a permanent electrical service sticker alongside the septic permit, which suggests electrical service is baked into the standard building process; I'd ask the Health Department and Building Inspector directly how that applies to a fully off-grid setup. source
Sun30-year normals
- Peak-sun hours, annual average
- 4.8 hrs/day
- Worst month (sizes an off-grid array)
- 3.1 hrs/day
- Yearly output per 1 kW of panels
- 1,356 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 43 in/yr
- Heating degree days
- 4,739 (moderate)
- Frost-free season
- Apr 16 to Oct 24
How far help isstraight-line
- Hospital
Ephraim McDowell James B. Haggin Hospital - 2.4 mi
- Fire station
Perryville Fire Department - 10.6 mi
- Hardware store
Lowe's - 12.9 mi
- Grocery
Kroger - 3.1 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 40330).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Mercer County, KY?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.