Off-Grid Living in Cowlitz County, Washington

I've been digging through Cowlitz County, Washington's code and county web pages to figure out what off-grid living actually looks like here, and the honest answer is: it depends a lot on whether your parcel is even zoned.

Zoning first. Cowlitz County's Land Use and Development Code (Chapter 18.10 CCC) is the official land use control for unincorporated areas, administered by the county's Department of Building and Planning. But here's the catch the county itself notes: only a portion of the county is actually zoned. If your land falls outside a zoned district, it's governed by the county's Comprehensive Plan instead of a specific district's rules. That means what you can build or do on raw land really varies parcel by parcel, and I'd call the Building and Planning office before assuming anything.

Dwellings. The county limits you to one manufactured home per lot (per CCC 18.10.585, with a narrow exception), and it has to carry a HUD insignia or a Washington L&I fire/life safety inspection approval. Park trailers can be permitted under Chapter 16.08 CCC if they're certified to ANSI A119.5 and approved by L&I. I didn't find county code that separately addresses tiny houses on wheels, so my read is they'd default to being treated like park-model RVs (temporary use), following the state baseline. Cottage housing (small permanent homes) is allowed under Chapter 18.68, capped at 1,200 square feet of habitable space, with a minimum tied to the state building code.

Building permits. The county has adopted the 2018 International Building and Residential Codes (plus mechanical, plumbing, fire, and energy codes) under CCC Title 16, per state mandate (RCW 19.27). Anything you build, alter, or occupy has to comply, and building permits run through the county.

Septic. The Environmental Health Unit (EHU) under Health & Human Services runs the on-site sewage program per state WAC 246-272A. You'll need a licensed designer's site evaluation and a permit application before you install anything, and the county requires ongoing operation and maintenance checks, homeowners can self-inspect most systems. Composting toilets fall under this same state framework; no separate county rule was confirmed.

Greywater. I only found county-specific greywater language for campgrounds. For a regular residential setup, it looks like the state WAC 246-274 baseline applies, administered locally by EHU.

Rainwater harvesting. No county ordinance turned up in my research here, so this defaults to state Department of Ecology policy, which generally doesn't require a water right for non-potable use.

Wells. EHU certifies potable water for individual and shared systems and issues well construction, maintenance, and abandonment permits. Water rights themselves (including the small-well exemption under RCW 90.44.050) are a state Ecology matter, not the county's.

Full utility disconnection isn't addressed as its own rule anywhere I found. Practically, it comes down to satisfying the building code, septic requirements, and water certification separately, there's no standalone "off-grid permit."

Bottom line: confirm your parcel's zoning status directly with the county before making plans.