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New rules coming our way for accessory dwelling units in rural areas

Chelan County Community Development encourages people with unpermitted, detached accessory dwelling units (ADU) that are outside an urban growth area to come in and talk with them before new state laws go into effect on July 1.

A bill recently passed by the state Legislature will impose higher fines and after-the-fact permitting fees on detached ADUs that are unpermitted and outside an urban growth area. The bill also includes several new regulations.

“We want to work with people before these new regulations and fines go into effect,” Community Development Director Deanna Walter said. “Come talk with us before you must abide by these new state-mandated rules. We will try to work with you to get you permitted and built to current compliance before the new rules hit.”

In an effort to ease the state’s housing crisis in rural areas, the state Legislature passed HB 1345, which allows one ADU, either attached or detached, on one parcel of land located outside an urban growth area, or UGA. Unincorporated Chelan County has allowed ADUs to be built on properties since 2011, so the implementation tools are already in place.

However, with the new legislation comes a variety of new regulations. These new regulations do not apply to any detached ADUs permitted in unincorporated Chelan County before July 1. But beginning on July 1:

  • A detached ADU is not allowed on nonconforming lots that are less than 1 acre.
  • The detached ADU must be metered for water.
  • The ADU’s gross floor area cannot be more than 1,296 square feet. This does not include porches or covered or uncovered decks.
  • The detached ADU must use the same driveway as the principal dwelling.
  • The detached ADU must be sited within 150 feet of the principal dwelling.
  • Detached ADUs will now count in density for zone and comprehensive plan designation.

After July 1, if the county identifies an unpermitted, detached ADU outside the UGA, the following fines and penalties will apply:

  • The owner will be issued a civil infraction of no less than $1,000.
  • The owner must pay triple the county’s after-the-fact building permit fees.
  • The ADU must be removed if it is not brought to existing standards, which include the Washington State Energy Code.
  • If an owner does not seek voluntary compliance and has already received a civil citation or fine, they will be prohibited from having an ADU on their property for at least three years.

“The new legislation intended to spur more housing options for people, but some of these new regulations are going to be costly for people found out of compliance after July 1,” Walter said. “If you own an unpermitted, detached ADU in one of our rural areas, don’t wait to contact us. We may be able to help you.”

Chelan County Community Development is at 316 Washington St., suite 301, in Wenatchee. You can reach the office at 509-667-6225. The new rules do not apply to permitted short-term rentals in Chelan County, which have separate permitting processes.

Last Updated: 03/18/2026 10:30 AM

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