Off-Grid Living in Washington County, Illinois

I've been digging into Washington County, Illinois for anyone thinking about building or living off-grid out there, and here's where things stand based on what I could confirm officially.

First, the good news for planning purposes: Washington County is not one of those rural Illinois counties with zero zoning. The county administers its own Revised Zoning Ordinance through its Zoning Department, and there's a zoning board of appeals with members from all three county board districts. That means raw land isn't a free-for-all, whatever you do with it will be checked against a county-level rulebook, not just left to the state's silence on zoning.

Where it gets murkier is dwellings, tiny homes, and RVs. I could not find an official Washington County page that spells out minimum dwelling size, tiny-home standards, or whether you can legally live in an RV on your land long-term. That likely lives somewhere in the zoning ordinance's fine print, but I'd call the Zoning Department directly rather than guess.

Building permits are similarly foggy at the county level. Illinois adopted a statewide building code as a default for jurisdictions without their own, but whether Washington County has its own adopted code or defers to the state's wasn't something I could confirm from the county's own materials. Again, the Zoning Department is your first call.

Septic and wells are on much firmer ground. The Washington County Health Department acts as the local agent for the Illinois Department of Public Health (IDPH) on both private sewage disposal systems and water well permitting. So septic tanks, seepage fields, and well construction are all permitted activities, but they go through the county Health Department's Environmental Services side, following IDPH's statewide standards.

Greywater reuse and rainwater harvesting are both unclear. I found no official county or state page that specifically addresses either one for residential use, so I'd treat these as open questions, worth a direct call to the Health Department to see how they'd classify a greywater system under the private sewage code, since it's plausible they'd fold it into that same review process.

Living fully off the utility grid, meaning no electric hookup and no municipal water or sewer, isn't explicitly addressed anywhere I could find. It would likely come down to how the zoning ordinance and whatever building code applies handle occupancy standards, which loops back to needing a direct conversation with the county.

Bottom line: Washington County has real zoning and a functioning health department for septic/well permitting, but a lot of the specifics that matter most for off-grid living (dwelling size, RV occupancy, greywater, rainwater, full grid disconnection) just aren't spelled out in what's publicly posted. Call before you build.