Grant County, WA Accessory Structures: ADU Rental Restrictions (2026)

020(c)(1)(C) makes that explicit: every ADU permitted under the section, whether attached, built into the primary home, or detached, must be occupied as a permanent residence, and it may not be used, rented, or leased as a transient short-term rental. The code defines that prohibited short-term use as anything under 30 consecutive days, which is the same threshold used across short-term rental regulation generally, meaning nightly or weekly bookings through platforms like Airbnb or Vrbo are off-limits for an ADU regardless of how the unit is configured or which zoning district it sits in.

This restriction sits inside the same subsection that sets the ADU configuration limits, so it applies uniformly whether the ADU is one of two units allowed in an urban growth area or the single detached unit allowed elsewhere in the unincorporated county. A long-term lease of 30 days or more, by contrast, is a permitted use of an ADU since the unit still functions as a permanent residence for the tenant. 020(c)(6), and continued short-term rental use after occupancy is a use violation of the underlying zoning approval rather than a separate licensing issue.