Off-Grid Living in Westchester County, New York

I'll be upfront: Westchester County is one of the trickier places in New York to research off-grid living because there's no countywide zoning code. Westchester has six cities, 16 towns, and 23 villages, and every one of them has home-rule authority over planning and zoning. That means the answer to "can I do this here" almost always comes down to which town or village line your parcel sits on, not anything the county government decides. The county's Planning Department mostly reviews referrals from municipalities and offers technical assistance; it doesn't write the zoning rules itself.

Where the county does have real teeth is public health, specifically septic systems, wells, and water quality. That's handled by the Westchester County Department of Health under the county's Sanitary Code (the Laws of Westchester County, Article VIII), and it's a genuinely stricter-than-baseline process. Any new or replacement onsite wastewater treatment system (what most people call a septic system) needs a construction permit and approved plans from the Health Department before you build, and before you can occupy the building. Plans have to be prepared by a licensed professional engineer, and county environmental engineers do field visits during construction. So if your off-grid plan involves a standard septic system, budget for a real design and review process, not just a DIY leach field.

Private wells are permitted, and Westchester is unusual in requiring well water testing not just at construction but also at property sale and for leased properties, under the county's Private Well Water Testing Law. You also need a construction permit through the Health Department's Bureau of Environmental Quality before drilling.

Composting toilets and greywater systems aren't spelled out separately on the county's public pages I found, so I'd treat them as folding into the same OWTS/Sanitary Code review rather than assuming they're exempt. Rainwater harvesting doesn't appear to have county-specific rules either, so state baseline rules would apply by default, but confirm with your town.

For dwellings, tiny houses, and RVs as permanent residences, I did not find an official Westchester County page settling the question. It's very likely to be a town-by-town zoning call, and some towns treat tiny homes on wheels the same as RVs (not permanent dwellings), so you really do need to pull the specific municipality's code off eCode360 or Municode.

Bottom line: the county sets the septic and well rules, hard and specific. Everything else, especially zoning and whether you can live disconnected from utilities, is a local decision you need to run down town by town. Don't assume what one Westchester town allows applies next door.