Do I Need a
Building Permit in Seattle?
Answer a few simple questions about your project and get instant guidance on permit requirements, estimated fees, review timelines, and the documents you'll need. Covers 14 project types across Seattle & King County.
When Do You Need a Building Permit in Seattle?
Seattle's permit requirements are among the most comprehensive in the Pacific Northwest. Here's a quick overview of what does and doesn't require a permit.
Permit Required
- Removing or moving load-bearing walls
- Moving or adding plumbing fixtures
- Adding new electrical circuits or panel upgrades
- Any addition (new square footage)
- ADU / DADU construction (WA HB 1337)
- Basement finishing (framing, electrical, plumbing)
- Decks over 30" above grade or 200+ sq ft
- Full re-roof (tear-off & replace)
- Garage conversion to living space
- New or relocated HVAC systems
- Changing window/door opening sizes
- Demolition of any structure
- Fences over 8 ft (Seattle) / 6 ft (most others)
- EV charger installation (new circuit)
No Permit Needed
- Painting, wallpapering, tiling, carpeting
- Cabinet replacement (same footprint)
- Countertop replacement (no plumbing changes)
- Replacing fixtures in same location (faucets, toilets)
- Replacing switches, outlets, light fixtures (same circuit)
- Fences under 8 ft in Seattle (6 ft elsewhere)
- Decks under 30" high, under 200 sq ft, freestanding
- Small sheds under 200 sq ft, single story
- Thermostat replacement
- Landscaping (no retaining walls over 4 ft)
- Driveway & sidewalk repair (not new construction)
- Window replacement (same size, same opening)
- Minor plumbing repairs (same location)
- HVAC maintenance (filters, cleaning)
Source: SDCI Tip Sheets, IRC 2021 §R105.2, SMC Chapter 23. Requirements may vary by specific project details and jurisdiction.
Seattle Building Permit Fees & Timelines (2026)
Kitchen Remodel
$850 - $2,550
Structural + trade permits
Source: SDCI 2026
Bathroom Remodel
$400 - $1,700
Plumbing + electrical permits
Source: SDCI 2026
Basement Finishing
$1,020 - $3,060
Building + trade permits
Source: SDCI 2026
Home Addition
$2,550 - $6,800
Full plan review required
Source: SDCI 2026
ADU / DADU
$3,400 - $10,200
Complex residential review
Source: SDCI 2026
Trade Permits
$150 - $500 each
Electrical, plumbing, mechanical
Source: SDCI 2026
5 Common Permit Mistakes Homeowners Make
Skipping Permits Entirely
Unpermitted work can result in fines up to $500/day, forced removal, and problems when selling your home. Insurance may also deny claims for unpermitted work.
Source: SDCI Enforcement
Hiring Unlicensed Contractors
WA law requires contractors to be licensed, bonded, and insured. Hiring unlicensed contractors voids your warranty protections and may make permits invalid.
Source: WA L&I
Starting Work Before Approval
Beginning construction before your permit is approved can lead to stop-work orders, re-inspection fees, and potential plan revisions. Always wait for the green light.
Source: SDCI
Not Getting Final Inspection
A permit without a final inspection is the same as no permit at all in the eyes of title companies and insurers. Always close out your permits.
Source: SDCI
Underestimating Timeline
SDCI review times can extend to 64+ days for residential projects. Factor permit review into your project timeline BEFORE scheduling contractors.
Source: SDCI Dashboard
Frequently Asked Questions About Seattle Building Permits
Do I need a building permit in Seattle?
In Seattle, you need a building permit from SDCI for any project involving structural changes, plumbing modifications, new electrical circuits, ventilation changes, additions, ADUs, or change of use. You do NOT need a permit for cosmetic work like painting, same-location fixture replacement, re-tiling, cabinet replacement (same footprint), or fences under 8 feet. Source: SDCI, IRC 2021 §R105.2.
How much does a building permit cost in Seattle?
Seattle building permit fees vary by project scope. A kitchen remodel with structural changes costs $850–$2,550 in permit fees. Bathroom permits run $400–$1,700. Deck permits cost $510–$1,360. ADU/DADU permits are the most expensive at $3,400–$10,200. SDCI's base hourly rate is $292/hour in 2026 (up 18% from 2025). Trade permits (electrical, plumbing, mechanical) typically cost $150–$500 each. Source: SDCI 2026 Fee Schedule.
How long does it take to get a building permit in Seattle?
Simple projects eligible for Subject to Field Inspection (STFI) — like re-roofs and water heater replacements — can be approved same-day. Standard residential projects take 4–8 weeks. Complex projects (additions, ADUs, garage conversions) take 8–16 weeks. SDCI's 75th percentile review time is 64 days. Source: SDCI Performance Dashboard.
Do I need a permit for a kitchen remodel in Seattle?
It depends on the scope. Cosmetic work (paint, countertops, same-layout cabinets) does NOT require a permit. You DO need permits if removing/moving walls (building permit), relocating plumbing (plumbing permit), adding circuits (electrical permit), or moving a gas line (mechanical permit). Source: SDCI Tip Sheets 201, 301, 401.
Do I need a permit to build a deck in Seattle?
A deck requires a permit if it is: over 30 inches above grade, over 200 square feet, or attached to the house. A small freestanding deck under 30" high and under 200 sq ft is exempt. Electrical outlets or lighting require a separate electrical permit. Fees: $510–$1,360. Source: IRC 2021 §R105.2, SDCI Tip 202.
Do I need a permit for a fence in Seattle?
In Seattle, fences under 8 feet do NOT require a permit — more lenient than most other cities (6 feet threshold). Corner lots have sight triangle restrictions. In Bellevue, Kirkland, Redmond, and most King County cities, fences over 6 feet require a permit. Source: SMC 23.44.016, SDCI Tip 203.
Do I need a permit to finish my basement in Seattle?
Yes — almost always. Finishing a basement requires permits for framing (building permit), electrical wiring (electrical permit), and plumbing if adding a bathroom (plumbing permit). Bedrooms require egress windows per IRC §R310 (min 5.7 sq ft opening). Converting to an ADU/rental needs the most extensive permitting including change of use. Source: SDCI, IRC 2021.
What happens if I do work without a permit in Seattle?
Unpermitted work in Seattle can result in: fines up to $500/day, stop-work orders, required removal of unpermitted work, difficulty selling your home (title companies flag open/missing permits), insurance claim denials, and liability issues. SDCI actively enforces permit compliance through complaints and inspections. It's always cheaper and safer to get the permit upfront. Source: SDCI Enforcement.
Let Us Handle the Permits
Giant Builders manages the entire permit process for every project — from applications and plan submissions to inspections and final approvals. Focus on your project, not paperwork.