Off-Grid Living in Sully County, South Dakota

I've been digging through the official Sully County, South Dakota records to figure out what's actually allowed if you want to live off-grid out there, and here's the honest picture.

Sully County, unlike some rural South Dakota counties, has adopted its own countywide zoning ordinance (effective 2003) and a subdivision ordinance. That matters because it means you can't just buy raw land and do whatever you want, the way you might in a truly unzoned SD county. Sully County's zoning applies to all unincorporated land outside Onida and Agar, and the Board of County Commissioners oversees platting decisions under the subdivision ordinance. I did not find any provision letting you skip zoning review for basic occupancy.

On dwellings, the zoning ordinance defines "dwelling" and "manufactured home" in fairly standard terms, but I could not find explicit county language on tiny homes on wheels or RVs used as permanent residences. That's a real gap, so if that's your plan, call Planning & Zoning before you commit.

Building permits are handled by the county's Planning & Zoning / Equalization office, which maintains its own fee schedule. South Dakota state law sets the 2021 International Building Code as the standard when a jurisdiction chooses to adopt building codes, but plenty of rural SD areas don't enforce a local building code at all. I could not confirm from official Sully County sources whether farm structures or owner-built homes get an exemption, so ask the county directly.

Septic systems are governed by state DANR rules requiring state-certified installers everywhere in South Dakota, and Sully County's Planning & Zoning office is the logical local point of contact, though I didn't find a Sully-specific septic ordinance text.

Greywater reuse: I found nothing official at the county or state level. Treat this as unclear and ask the county.

Rainwater harvesting isn't explicitly addressed either, though the state's domestic-use water rights exemption (up to 25,920 gallons/day) is worth knowing about since it shapes how "domestic use" is treated generally.

Private wells fall under DANR's Water Rights Program statewide. Domestic wells are usually exempt from a water rights permit unless you exceed that same daily/peak-rate threshold, and any licensed driller must file a well completion report with the state.

Living off-grid, unhooked from electric or municipal utilities, doesn't appear to be banned by county or state law, but your septic and well setups still have to clear their own approvals, which functions as a practical requirement even without a direct "utility mandate."

Bottom line: Sully County is more regulated than a no-zoning county, but plenty of the specific off-grid questions (tiny homes, greywater, rainwater) just aren't spelled out in what I could find. Call the county before you buy or build.