Off-grid site report

Cowlitz County, WA

46.1461, -122.9225 · 20 ft elevation

Read this before you act on anything below. This is my researched starting point for Cowlitz County, WA, not legal advice and not a guarantee. Rules change, and the deciding facts on any specific parcel (setbacks, perc results, overlay districts, deed restrictions, road frontage) live at the county or town office, not in any database. Before you buy land or build, confirm the current rules directly with the local zoning and health offices - the sources on this page tell you exactly who to call.

The local rulesCowlitz County, WA

Zoning & raw-land occupancy

Varies locallyCowlitz County's Land Use and Development Code (Chapter 18.10 CCC) governs zoned unincorporated areas, but only part of the county is actually zoned; unzoned land falls under the Comprehensive Plan. Confirm your specific parcel's status with the county. source

Dwellings, tiny homes & RVs

Varies locallyManufactured homes are capped at one per lot and need HUD or state L&I approval; park trailers need ANSI/L&I certification; cottage housing up to 1,200 sq ft is allowed under Chapter 18.68 CCC. Tiny houses on wheels aren't separately addressed in county code. source

Building permits & codes

Generally allowedCowlitz County enforces the 2018 International Building and Residential Codes under CCC Title 16, per state mandate, and requires permits for construction, alteration, and occupancy. source

Septic & composting toilets

Generally allowedThe county's Environmental Health Unit administers septic permitting and ongoing O&M requirements under state WAC 246-272A; composting toilets fall under the same state framework with no separate county rule confirmed. source

Greywater reuse

Unclear - verifyOnly campground greywater rules were found in county code; residential greywater reuse appears to default to the state WAC 246-274 baseline, administered locally by the Environmental Health Unit. Ask EHU to confirm. source

Rainwater harvesting

Unclear - verifyNo Cowlitz County ordinance on rainwater harvesting was found; this likely defaults to Washington Department of Ecology's general policy allowing non-potable collection without a water right.

Private wells & water rights

Varies locallyThe county's Environmental Health Unit certifies potable water and issues well construction/maintenance/abandonment permits, while the state Department of Ecology controls water rights and the small-well exemption under RCW 90.44.050. source

Living disconnected from utilities

Unclear - verifyNo standalone county rule on full utility disconnection was found; in practice it depends on meeting the county's building, septic, and water certification requirements separately.

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 3.7 hrs/day
Worst month (sizes an off-grid array): 1.5 hrs/day
Yearly output per 1 kW of panels: 1,017 kWh

JFMAMJJASOND

Weather1991-2020

Precipitation: 48 in/yr
Heating degree days: 4,684 (moderate)
Frost-free season: Apr 6 to Nov 11

How far help isstraight-line

Hospital PeaceHealth St. John Medical Center: 1.4 mi
Fire station Cowlitz 2: 0.8 mi
Hardware store Harbor Freight Tools: 0.1 mi
Grocery Grocery Outlet: 0.3 mi

From OpenStreetMap. Road miles will be longer, often much longer in hill country.

Plan this spot

These open with this location's real numbers already filled in (ZIP 98626).

Size a solar system Heat loss & insulation Firewood per winter Rainwater harvest Garden size Panel tilt

Sources: US Census Bureau geocoder; NLR PVWatts v8 (solar); NOAA NCEI 1991-2020 climate normals (nearest station) or Open-Meteo (ZIP-centroid) for weather; Open-Elevation; OpenStreetMap contributors. Public data retrieved Aug 21, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.