Zoning, building permits and septic rules in Bothell, Washington

Bothell’s own rules

• Building permitRequired

  Construction, alteration, repair, movement, demolition, occupancy change, and regulated system work inside Bothell city limits.

  • Listed exemptions in BMC 20.02.095(B) remain exempt, including certain small accessory structures, fences, minor work, public-service-agency work, and limited grading.

  “Permits are required to be obtained in order to have your construction plans reviewed for code compliance prior to starting the work, and also to have the work inspected.”

• InspectionsLimited

  Existing accessory dwelling units created without a building permit inside Bothell city limits.

  • Inspection determines whether the structure is sound, safe, and meets BMC 12.14.135 and Title 20.

  “If an accessory dwelling unit was created without a building permit, the city shall require a building inspection to determine whether the structure is sound, will not pose a hazard to people or property, and meets the requirements of this section and BMC Title 20.”

• Local zoningPresent (with conditions)

  Land inside Bothell city limits.

  • Uses and dimensional controls vary by zoning classification and subarea.

  “New Zoning Codes effective January 1st, 2025”

• Accessory dwellingsAllowed (with conditions)

  Accessory dwelling units on lots inside Bothell city limits.

  • Two ADUs are allowed per lot, except one is allowed on a lot developed with middle housing and one is allowed on lots designated with critical areas or buffers.
  • An ADU may be up to 1,200 square feet, subject to the stated conversion exception.
  • Detached ADUs have stated height limits.

  maximum ADUs per lot: 2 ADUs (One ADU on lots with middle housing or critical areas/buffers) · maximum ADU size: <= 1200 square feet (Existing-space conversion may exceed it with community development director approval, up to 40% of the primary dwelling's gross floor area)

  “Accessory dwelling units are permitted subject to the following requirements:”

• Permit processPartial

  Work requiring a building permit inside Bothell city limits.

  • Applicant must apply to the building official and obtain the required permit before the described work.
  • Exempt work remains subject to other applicable laws and ordinances.

  “All permit and land use applications are accepted online only, through www.MyBuildingPermit.com.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Bothell or King County directly.

• Owner-builder exemption — Owner-built residential work inside Bothell city limits.
• Certificate of occupancy — Buildings and structures inside Bothell city limits.
• Minimum dwelling size — Dwellings inside Bothell city limits.
• Living in an RV — RV occupancy on private land inside Bothell city limits.
• Camping on your land — Temporary camping on private land inside Bothell city limits.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Off-grid gear

Going off-grid in Bothell means bringing your own water and power. The kit we’d start with:

• Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
• Power Bluetti Solar generators and home battery backup for living off the grid.
• Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
• Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.

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