Addition permits in City of Bellevue: fees, timeline & requirements (2026)

When does a home addition need a permit in City of Bellevue?

The Single-Family Addition (BR) permit covers adding LESS THAN 3,000 square feet, or a deck, to an existing single-family residence. At 3,000 square feet or more Bellevue routes the work to its New House Construction or Large Addition permit instead. The BR permit also covers an attached garage or carport, detached buildings such as garages and sheds, retaining walls over four feet, a deck or deck with spa and replacement of existing deck structural framing, a dock, boat house, boat lift or bulkhead over four feet, and a swimming pool, bathing pool or hot tub 24 inches or more deep and in-ground. One BR permit carries the clearing and grading, any required demolition, electrical (except temporary power), mechanical (except fire protection) and plumbing with it — those are not separate applications.

How City of Bellevue adopted this rule

The threshold comes from the state code (WAC 51.51), which City of Bellevue adopts by reference in the provision quoted below.

“The following codes, all as amended, added to, or excepted in this chapter, together with all amendments and additions provided in this title, are adopted and shall be applicable within the city of Bellevue: A. International Building Code. 1. Code Adoption.”

Source ↗verified 2026-05-17

What City of Bellevue says in its own permit handout

From Single Family Addition Permits, published by City of Bellevue. This is the jurisdiction's own guidance on its permit process, not the ordinance text — where the two differ, the code governs.

“Additions greater than 3,000 gross square feet of new and/or replaced floor area require a one- or two-family combo permit (BS).”

Handout ↗read 2026-09-05

Required submittals

• Architectural Plan (Bellevue SF Addition Permit — Required Documents)
• Boundary and Topographic Survey
• Construction Stormwater Pollution Prevention Plan (CSWPPP) — CSWPPP Short Form acceptable for projects with <7,000 sf clearing and <100 cu yd grading
• Energy Code Sheet or Envelope Summary (Residential Energy Code Worksheet)
• Residential Site Plan
• Storm Drainage Report
• Stormwater Site Plan
• Structural and Lateral Calculations
• Structural Plan
• Value of Improvements Form
• Geotechnical Report (per Bellevue Geotechnical Report Requirements — required for clearing/grading permits and slope/groundwater-sensitive sites)
• Critical Areas or Shoreline Land Use Permit — when site in critical area or shoreline overlay
• King County Health Department Approval — required for septic tank installation or if dwelling served by septic system AND there is a private well on property
• Title Report

Inspection sequence

1. foundation/footing
2. plumbing rough-in
3. electrical rough-in
4. mechanical rough-in
5. framing
6. insulation
7. drywall
8. final

Contractor specialties needed

general, electrical-01-or-02, plumbing, mechanical

Notes & caveats

Submittals pulled verbatim from the Bellevue Single-Family Addition Permit page (verified 2026-05-17). MBP submission path: Application=Building / Project=Single Family Residential / Activity=Addition. Document Waiver Form may be uploaded in place of a required document if it does not apply. Permit Center contact: 425-452-4898 / [email protected]. Building Review: 425-452-4121 / [email protected].

Addition permit fee — Washington baseline, not City of Bellevue's own schedule

Worked example for a $120,000 home addition project (building permit). Your actual fee scales with project valuation.

Plan-review fee scales with valuation per UBC Table 1-A. State surcharge $6.50 per building permit. Trade permits (E/P/M) separate. Apply via https://mybuildingpermit.com. We have not read City of Bellevue's adopted fee schedule, so this is not City of Bellevue's fee: it walks the standard valuation table most Washington cities adopt by reference, as a rough guide. The real numbers are in City of Bellevue's fee schedule ↗. Impact/utility fees may apply separately.