Addition permits in City of Federal Way: fees, timeline & requirements (2026)
Everything you need to know about pulling a home addition permit in City of Federal Way, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Apply via MyBuildingPermit.com..
When does a home addition need a permit in City of Federal Way?
Any increase to building footprint or conditioned floor area requires a building permit. A Certificate of Water Availability with fire-flow calculations is required for additions or any change to the building footprint.
From City of Federal Way's own page
“Certificate of Water Availability (for additions or any changes to building footprint) w/Fire Flow Calculations.”Source ↗verified 2026-06-26
Required submittals
- Building Permit Application
- Single Family Remodel Checklist (#156)
- Complete set of drawings
- Structural calculations (if structural alterations)
- Floor plan + framing plan + building cross sections
- Certificate of Water Availability w/ fire-flow calculations
- Smoke/CO detector notes
Inspection sequence
- foundation/footing
- plumbing rough-in
- electrical rough-in
- mechanical rough-in
- framing
- insulation
- drywall
- final
Contractor specialties needed
general, electrical-01-or-02, plumbing, mechanical
Notes & caveats
2021 IRC R301 governs framing. WSEC R402.1 sets envelope requirements. New conditioned space requires Manual J HVAC sizing. Lateral load path continuity required for vertical additions. Most WA cities use a uniform fee bracket (UBC Table 1-A) for the building permit; plan review fee is typically 65% of building permit fee.
Addition permit fee estimate in City of Federal Way
Worked example for a $120,000 home addition project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $1,105.75 |
| Plan review | $718.74 |
| WA state surcharge | $4.5 |
| Estimated total | $1,828.99 |
Plan-review fee scales with valuation per UBC Table 1-A. State surcharge $4.50 per building permit. Trade permits (E/P/M) separate. Computed from the City of Federal Way fee bracket schedule · source ↗. Impact/utility fees may apply separately.
How to apply
- 1. Confirm your parcel's zoning & overlays. Run an address lookup for your City of Federal Way home addition — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
- 2. Assemble submittals (7).
- 3. Submit through the city portal: Apply via MyBuildingPermit.com. ↗
- 4. Track review (typical: 30–120 days). Respond to reviewer comments promptly.
- 5. Pay issuance fees (Plan-review fee scales with valuation per UBC Table 1-A. State surcharge $4.50 per building permit. Trade permits (E/P/M) separate.) and pick up the permit. Inspection card travels with the job.
Addition permits in City of Federal Way — FAQ
When does a home addition need a permit in City of Federal Way?
Any increase to building footprint or conditioned floor area requires a building permit. A Certificate of Water Availability with fire-flow calculations is required for additions or any change to the building footprint.
How much does a home addition permit cost in City of Federal Way?
For a $120,000 home addition project, the estimated City of Federal Way permit fee is about $1,828.99 — building fee $1,105.75 + plan review $718.74 + surcharges. Fees scale with project valuation per the city schedule.
How long does City of Federal Way take to review a home addition permit?
Typical review window: 30–120 days.