Off-Grid Living in Lewis County, Washington

I've been digging into what it actually takes to live off-grid in Lewis County, Washington, and the short version is: it's doable, but it's not a legal free-for-all. Unlike some rural Washington counties that skip zoning altogether, Lewis County has countywide zoning adopted under its county code (Title 17), so what you can do with raw land depends heavily on which rural zone you're sitting in.

Zoning. The county divides rural land into different zoning districts, each with its own permitted-use chart. Most rural zones call for a minimum lot size around one dwelling unit per five acres, but this varies by district (resource lands, rural development districts, etc.), so I'd pull up the county's zoning map before assuming anything about your specific parcel.

Dwellings, tiny homes, RVs. This is where a lot of off-grid dreams run into friction. Lewis County treats an RV or park trailer that's occupied continuously for more than 60 days the same as a mobile home, which means it has to meet mobile-home siting and inspection standards, unless it's in a licensed RV park or being used for temporary construction-site housing. Used mobile homes need an approved inspection insignia (state Labor & Industries or HUD) before they can be sited. Tiny houses on permanent foundations fall under the general state building code, and while ADUs are allowed in the county, I couldn't confirm exact size/bedroom limits from an official code citation, so check with the county planning office directly.

Building permits. Lewis County Community Development requires a permit for constructing, enlarging, altering, moving, or changing the occupancy of nearly any structure. The county's process typically starts with a Master Site Review, where planning staff check your proposal against zoning and critical areas rules and flag which additional permits (septic, water, building) you'll need before you go further.

Septic and composting toilets. The county's Onsite Sewage Program handles septic permitting, including soil testing, and covers systems up to fairly large daily capacities. Composting toilets registered under state health rules are allowed too, but any work beyond the tank itself needs a permit.

Greywater. I couldn't find a Lewis County-specific greywater ordinance; this appears to default to Washington State Department of Health rules.

Rainwater harvesting is permitted under Washington Department of Ecology's statewide policy, with the caveat that harvested water must be used on the same property and collected from existing, non-dedicated structures. No added county restriction turned up.

Wells and water rights. Small domestic wells generally fall under the state's groundwater permit exemption (capped around small daily quantities), administered by Ecology's Southwest Regional Office. Lewis County's own Water Program handles Group B small water systems and well-site inspections.

Full utility disconnection isn't separately banned, but practically speaking you'll need an approved septic or composting system and an approved water source cleared through the Master Site Review before the building department signs off on anything.

Bottom line: check your zone, start with Master Site Review, and don't skip the septic and water sign-offs.