Bothell DADU Permits: Documents, Utilities and Fees
Bothell’s ADU checklist calls for an assigned-address letter and, for new floor area, utility availability and fire-flow documents. Prepare those alongside the building and site plans before submitting through MyBuildingPermit.
Sources checked November 5, 2026. Confirm the requirements for your parcel with its permitting authority.
What should you resolve before submitting?
The city’s 3f checklist provides the application path and tells applicants to verify any non-applicable item with the relevant department. Use the checklist dated December 2025 with its listed 2026 fees as the starting document, then confirm any later city changes.
- Obtain or confirm the city’s address assignment.
- Identify the water and wastewater providers.
- Coordinate the required availability and fire-flow information.
- Prepare the site, building and energy documents.
- Submit the complete applicable package and initial payment.
Official guidance: Bothell ADU checklist with 2026 fees.
Why do the utility certificates matter?
The checklist identifies water and sewer availability certification and a fire-flow letter for projects adding new floor area. If Bothell supplies water, it directs applicants to submit the city’s availability request before the ADU application; it lists up to two weeks for that availability processing.
If another district is the provider, use that provider’s certification process. A city permit-office response and a water-district response answer different questions. Retain both with the drawing set.
Official guidance: Bothell ADU checklist with 2026 fees.
What does the 2026 checklist say about fees?
| Selected item | Published figure or basis |
|---|---|
| Single-family planning review | $231 |
| Residential site review and inspection for a new building | $834 |
| Detached-ADU plumbing and mechanical fees | 8% of the building permit fee each |
| Technology fee | 5% on the categories specified in the checklist |
The checklist separates application and issuance charges. These selected figures are not an all-inclusive permit total. Identify the building, impact, stormwater, trade and other applicable charges in the fee request.
Official guidance: Bothell ADU checklist with 2026 fees.
How do you keep the site and building package aligned?
Use the same address, proposed building location and service routes in the application documents. If a provider requires a different connection approach, update the affected plans before treating the budget as complete.
TimberworX offers a free Bothell DADU consultation. Detailed design and budgeting are paid preconstruction services. Bring the property records and any provider responses to establish the next tasks.
A few things to know
Does a $231 planning-review line represent all permit costs?
No. The city checklist lists additional categories and payments.
Can I skip an item that appears irrelevant?
The city checklist asks you to verify non-applicable items with the relevant department before submission.
Keep planning
Bothell DADU Size Limits: Can You Build 1,200 Sq Ft?
Bothell’s current ADU code allows up to 1,200 square feet and sets detached-unit height limits. Understand exceptions before planning a cottage.
Can a DADU use septic or existing utilities?
Check septic capacity, sewer availability, water service and utility routes before committing to a DADU design in King County.
What permits do you need for a DADU?
A practical DADU permit checklist covering site plans, building review, utilities, trade permits and final inspections.