Bellevue ADU Permit Process
The full Bellevue, WA ADU permit pipeline from pre-application through certificate of occupancy. 5 phases, current fees, review department contacts.
Last updated 2026-05-15
- Timeline1–2 wkFees$200–$500DepartmentBellevue Development Services
- Timeline8–14 wkFees$4,500–$9,000DepartmentBellevue Development Services
- Timeline2–6 wkFees$0–$1,500DepartmentBellevue Development Services
- PHASE_04Permit IssuedDetails →Timeline1–1 wkFeesIncludedDepartmentBellevue Development Services
- Timeline18–30 wkFees$1,200–$3,500DepartmentBellevue Development Services
Bellevue permit resources
Frequently asked
What is the current Bellevue, WA ADU permit timeline?
Median Bellevue ADU permit issuance from clean submittal is 8–16 weeks in 2026. That breaks down as: intake + completeness check (5–10 business days), first review cycle (4–7 weeks across building, planning, side-sewer, addressing, drainage as applicable), corrections back to us (1–2 weeks), second review (2–4 weeks), then issuance. Pre-application meetings shave one full cycle on average. The fastest Bellevue ADU we have closed in 2025 was 6.5 weeks on a catalog plan with a pre-app; the slowest was 22 weeks because of a side-sewer easement title issue — not a planning issue.
What reviews are required for an ADU in Bellevue?
Standard Bellevue ADU review touches building, planning (zoning, lot coverage, setbacks), addressing, side-sewer (or septic where applicable), water availability, drainage review (if impervious exceeds threshold), and energy review (IECC R406 worksheet). Critical-areas review triggers if your lot is mapped for steep slope, wetland, riparian, or landslide hazard. SEPA review is rare for a single ADU but possible if other land-use actions are pending on the same parcel. Each review runs in parallel, not sequentially, which is why pre-app meetings matter.
What gets Bellevue ADU permits rejected on first review?
Top six Bellevue reviewer redlines we see: (1) IECC R406 envelope worksheet missing or calculations not matching plan assemblies; (2) side-sewer not shown on site plan with slope and invert; (3) lot coverage math omits roof overhangs (count to drip line in Bellevue); (4) Fire separation between primary and ADU walls insufficient when separation < 5 ft; (5) glazing U-factor or SHGC on schedule doesn't match window NFRC labels; (6) drainage report missing when impervious increase is over the threshold. We catch all six in our QA before submittal.
Can I expedite the Bellevue ADU permit?
Bellevue does not offer formal paid expedite for residential ADUs, but the practical accelerators are: catalog plans (reviewers see familiar details and move fast), complete drainage report at submittal, pre-app meeting on file, and using a contractor whose past submittals were clean. We track our own correction count per submittal; clean sets average 1.2 review cycles in Bellevue versus the city-wide 1.8 average. Pre-app meetings are free and currently scheduling 3–4 weeks out — book one before drawings start.