Building a private compound in Washington

Water

Washington's Department of Ecology administers water rights. State law exempts small domestic wells, up to 5,000 gallons a day, from permits. After the 2016 Hirst decision and the 2018 law that followed, new domestic-only exempt wells in many watersheds are limited to 3,000 or 950 gallons a day per connection depending on the watershed plan, and carry a $500 fee. Some counties still require proof of water adequacy before a building permit. We confirm the rules for the specific watershed before purchase.

Collecting rainwater from existing roofs for use on site needs no water right, but using it as the primary drinking source for a new home is a county decision, and many counties do not allow it.

Building codes

Washington adopts a statewide residential code based on the International Residential Code, enforced by local jurisdictions. The 2021 edition took effect in March 2024.

Climate and growing season

Washington spans zones 4b to 9a. Approximate frost-free seasons run about 220 days around Seattle and 190 to 200 around Walla Walla, dropping to about 150 to 170 around Spokane and Yakima.

Hazards

Wildfire and drought lead Washington's billion-dollar disasters in NOAA's records. Western Washington faces earthquake and volcanic hazards, which we evaluate on any site there.

Taxes

Washington has no tax on wages, but it does levy a capital gains excise tax on large long-term gains and has a high average combined sales tax. Clients planning major asset sales should review this with their tax advisor.

Our view

Eastern Washington offers drier land, space and lower density; western Washington offers water and forest. Either way, the watershed's exempt-well rules are the first diligence item.

This guide is general information, current to October 2026, and not legal, tax or water-rights advice. Water and building rules change and vary by county and basin. We verify every requirement for a specific parcel with the responsible agency before purchase.