Off-Grid Living in Pierce County, Washington

I've been digging through Pierce County, Washington's rules for anyone dreaming of an off-grid setup here, and the short version is: it's doable in pieces, but a fully off-grid new-build home is going to run into real friction at the permitting counter. Here's what I found, broken down by topic, with the authority named for each rule.

Zoning. Pierce County runs a countywide zoning code (Title 18A, Pierce County Development Regulations), so unlike some rural counties there's no zoning-free zone here. What you can do on a given parcel, raw-land camping, RVs, ag use, depends entirely on its zone classification. The county's "About My Property" tool through Planning and Land Services (PALS) is the way to check your specific parcel before assuming anything.

Dwellings and tiny homes. Pierce County does allow tiny homes on permanent foundations, treating them like any other single-family residence under the International Residential Code and state energy code. But the county's own tiny-home guide is blunt: approved water supply and approved sewage disposal are required, and it explicitly says composting/incinerator toilets and rainwater catchment for potable water are not allowed as substitutes. Park-model RVs and tiny homes on wheels are treated as recreational, not permanent dwellings.

Building permits. Standard construction permitting applies to tiny homes just like any house, through the Building Official at the county's Development Center. Small accessory structures under 200 square feet (think tool sheds) may skip a building permit, but setbacks still apply.

Septic and composting toilets. The Tacoma-Pierce County Health Department (TPCHD) administers the state's on-site sewage code (WAC 246-272A) and layers on its own requirement of annual inspections for pressure distribution systems. Composting toilets aren't accepted as the primary sewage system for new permitted dwellings.

Greywater. I couldn't find a Pierce-County-specific greywater ordinance. This appears to inherit the state WAC 246-274 baseline through TPCHD, but I'd confirm directly with them since I found no clear local text.

Rainwater. Not allowed as a potable source for permitted dwellings per the county's tiny-home guide. Non-potable rainwater use (irrigation etc.) isn't clearly addressed locally and likely falls back on state Ecology rules.

Wells. Permitted, but layered: state Department of Ecology and Department of Health standards (WAC 173-160, WAC 246-290) apply, and TPCHD administers local well permitting, including bacteriological/flow testing and, in some areas, a hydrogeologic report per county PALS policy.

Bottom line on going fully off-grid. There's no single ordinance banning it, but new permanent construction has to clear water and sewage requirements that rule out rainwater-as-potable and composting-only setups. Existing, legally established off-grid properties may be a different story, though I couldn't confirm how the county treats those.

Always double check specifics with the offices below before you buy land or break ground.