Off-Grid Living in Columbia County, Washington

I've been digging into what it actually takes to live off-grid in Columbia County, Washington, and here's the honest picture.

Columbia County runs countywide zoning through its Planning and Building Department, which is a bit unusual in that it also provides building services for Dayton, Waitsburg, Starbuck, and even neighboring Garfield County. That's worth knowing because it means your permit paperwork may run through the same office regardless of which town or unincorporated area you land in, but the underlying zoning rules can still differ if you're inside Dayton's city limits versus the county's unincorporated land. The county's zoning ordinance governs the basics you'd expect: allowed uses, lot sizes, setbacks, height limits.

On dwellings, the county is fairly restrictive about mobile and manufactured homes: you generally need a siting permit before one can be occupied on a property, outside of licensed sales or storage lots. RVs are treated as strictly temporary, capped at 15 days occupancy in a six-month window unless you get specific approval, with anything past 30 days needing to be tied to an approved RV park permit. I did not find a standalone tiny-house-on-wheels ordinance, so I'd treat that as governed by the RV rule until you confirm otherwise with the county.

Building permits are required for essentially all construction, plumbing, mechanical, and electrical work, and you'd get those through the Columbia County Planning and Building Department, though electrical and manufactured-home installation permits actually route through the state Department of Labor & Industries.

Septic systems (called OSS, on-site sewage systems) are reviewed by Columbia County Public Health, which also handles land development review tied to lot suitability. This is the county's local implementation of the statewide DOH septic rule. Composting toilets aren't spelled out on the county's own pages, so I'd confirm directly with Public Health whether they'll accept one in place of a conventional system.

Greywater reuse and rainwater harvesting don't have county-specific pages that I could find. Both would default to Washington State's baseline rules, administered locally by Columbia County Public Health for greywater, and generally unregulated for basic non-potable rainwater catchment.

Wells are permitted but come with statewide process: you (or your driller) file a Notice of Intent with the Department of Ecology at least 72 hours before drilling, and exempt-well quantity limits apply. Ecology's Eastern Region office handles the help desk for Columbia County. Public Health can help with well maintenance and decommissioning guidance too.

There's no standalone county ordinance that flatly bans or blesses full utility disconnection. In practice, going off-grid here means satisfying the separate building, septic, and water pieces individually, since nothing forces you onto the grid outright, but nothing exempts you from those underlying permit requirements either.