Off-Grid Living in San Juan County, Washington

I've been digging into San Juan County, Washington for anyone dreaming of an off-grid setup on the islands, and it's a genuinely interesting case, because this is one of the few places in the state where the county has officially embraced rainwater as a primary drinking water source. That said, there's a lot of nuance here, and most of it flows down from the county's Unified Development Code (Title 18 SJCC) and Health & Community Services regulations (Title 8 SJCC), layered on top of state law.

Zoning is countywide here, unlike a lot of rural counties, but what you can actually do on a parcel depends heavily on its land use designation under the Comprehensive Plan (growth areas, activity centers, rural lands, resource lands), plus shoreline overlay rules if you're anywhere near the water. This is squarely a San Juan County Department of Community Development matter, and I'd call them before assuming anything about a specific parcel.

RVs and tiny homes get specific, and somewhat restrictive, treatment. The county's own guidance says RVs aren't treated as dwelling units, most land use designations only allow one RV per property, RVs can't be used as rentals, and if occupied beyond a certain stretch it has to be the owner or immediate family only. Tiny homes on wheels are treated similarly. Neither RVs nor tiny homes can be permanently sited on shoreline-jurisdiction land.

Septic is state-framework (WAC 246-272A) but San Juan County adds its own layer: installers need a county license, not just a state one, and the county runs a Homeowner O&M certification class so owners can self-inspect conventional systems (proprietary systems like Advantex or Orenco still need a certified inspector).

Greywater permits are issued by county Health & Community Services, following the state's WAC 246-274 standard, no local loosening found.

Rainwater harvesting is the standout: the county's site says no water right is needed for rooftop rainwater collection and storage, and its Certificate of Water Availability process (Chapter 8.06 SJCC) explicitly lists "alternative water sources" as one of three acceptable ways to satisfy water availability for a building permit. Washington's Department of Ecology confirms San Juan is one of the areas where rainwater may be the only feasible primary supply, but it directs you to confirm with county planning first.

Wells follow the state's small-domestic-use exemption from a formal water right, but the county still requires a Certificate of Water Availability tied to any building permit, satisfied by a purveyor letter, a qualifying well, or the rainwater alternative above.

Full utility disconnection isn't addressed as its own policy; it just falls out of satisfying the septic, water-availability, and building code pieces individually. Nothing prohibits going off-grid outright, but you're threading several permits, not skipping them.