Off-Grid Living in McHenry County, Illinois

If you're looking at land in McHenry County, Illinois, the first thing I'd nail down is whether that parcel is inside a city or village or out in unincorporated territory. That one fact changes everything, because McHenry County's own zoning, building, and permitting rules (run out of the Planning and Development Department) only apply in unincorporated areas. If you're inside McHenry, Woodstock, Crystal Lake, Algonquin, or any other municipality, that town's own code takes over and you have to check with them separately, not the county.

For unincorporated land, the county's Planning, Zoning and Land Use Division handles rezoning, conditional use permits, variations, and subdivision questions under the county's Unified Development Ordinance. They're also the ones who can write a "buildability" letter telling you whether a specific parcel can legally support a home.

On tiny homes and RVs as permanent dwellings, I couldn't find an official county document spelling out a minimum floor area or an explicit RV-residency rule. That doesn't mean anything goes, it just means this falls into a gray zone that's effectively governed by the adopted building code and local zoning, and you'd want to call Planning & Development directly before assuming you can live in an RV or micro-cabin full time.

Building permits are required for most construction in unincorporated areas, and as of 2023 the county reviews new applications against the 2021 ICC codes and 2020 NEC. Small accessory structures (150 square feet or less, out of the floodplain/wetlands) may be exempt from a permit, but anything bigger needs one.

Septic is tightly regulated. The McHenry County Department of Health issues permits for installing, modifying, or abandoning any septic system, and Illinois-licensed contractors must do the work. Aerobic treatment units are allowed if they discharge into a compliant subsurface system, surface-discharging systems are banned, and holding tanks are only allowed as a stopgap, not a long-term solution. Composting toilets aren't specifically addressed at the county level, so that would default to the Illinois Department of Public Health's statewide framework.

Greywater reuse and rainwater harvesting are both open questions. I found no county or state page directly authorizing or restricting either one for residential use in McHenry County, so I'd call the Health Department's Environmental Health Division before setting up a greywater system or rain catchment and assuming it's fine.

Wells are county-permitted under state rules, since the whole county relies on groundwater. You'll need a permit to drill, repair, or abandon a well, and the county recommends testing your own water for bacteria and nitrates since private wells aren't regulated the way public systems are.

There's no standalone county rule I found on simply disconnecting from the grid. Practically, though, your ability to live off-grid comes down to whether your dwelling meets the building code and has an approved well and septic system, both of which require permits either way.