Do I need a permit in Des Moines, WA?
Des Moines sits in the Puget Sound region with a shallow 12-inch frost depth, which dramatically changes foundation and deck requirements compared to inland Washington. The City of Des Moines Building Department administers permits under the Washington State Building Code (currently the 2018 IBC/IRC with state amendments). Most residential projects — decks, fences, additions, electrical work, and roof replacements — require a permit. The department processes applications in person at City Hall; turnaround for plan review typically runs 2–4 weeks depending on project complexity. Owner-builders are allowed for owner-occupied residential work, but you must pull the permit yourself and arrange all required inspections. Skipping a permit exposes you to costly corrections, insurance claim denials, and resale complications — most mortgage lenders and title companies will flag unpermitted work during closing.
What's specific to Des Moines permits
Des Moines' shallow 12-inch frost depth is the most important local factor. This applies to the Puget Sound side of the city and areas with known frost-susceptible soils. Deck footings, foundation walls, and utility lines must go below 12 inches to avoid frost heave — much shallower than the 36–48 inches required in eastern Washington or colder regions. The IRC allows this shallow depth in Zone 4C maritime climates, but your engineer or contractor must call it out explicitly on the plans. If you're pushing the limits on a DIY deck, this is worth a pre-submission conversation with the building department.
The City of Des Moines Building Department is small compared to King County or Seattle. Applications are filed in person at City Hall during business hours (Monday–Friday, 8 AM–5 PM; verify current hours before you go). The city does not currently offer online permit submission, though you can submit plans by appointment or mail. Over-the-counter permits — fences under 6 feet, typical residential electrical subpermits, water heater replacements — can often be approved same-day if the application is complete. Bring two copies of your site plan and construction drawings; the department will stamp and return one to you.
Washington State Building Code adoption includes amendments that reflect Puget Sound marine conditions and seismic risk. The 2018 IBC/IRC (Washington State Edition) is the current standard. This means snow loads, wind speeds, and seismic design categories for Des Moines are codified by the state — not negotiable by the city. Your contractor or designer should reference these values during design; the building department will check them during plan review. Seismic is particularly relevant for larger additions, new construction, and braced wall design.
Permit fees in Des Moines are based on construction valuation. A typical residential permit ranges from $100 for a fence or small electrical job to $500–$1,500 for a deck or room addition. Plan-check fees and inspection fees are included in most base permits; there are usually no surprise add-ons. Ask for a fee estimate when you call or visit — the staff can quote you based on your project scope. Payment is cash or check at the time of application (verify payment methods locally).
The city requires a site plan showing property lines, setbacks, and lot coverage for most residential projects. Corner-lot permits often need an additional sight-line clearance or variance if the project is near the right-of-way. Wetlands and critical areas are not common in central Des Moines, but if your property is near a water body or sensitive area, the city may require an environmental review or critical-areas statement. Call ahead if your lot is anywhere near Miller Park or Green Cove — the department will tell you if additional review is needed.
Most common Des Moines permit projects
These are the projects that trigger the most permit applications in Des Moines. Each one has specific local rules — click through to learn what you need to file, what it costs, and what inspections to expect.
Decks
Any attached or freestanding deck over 30 inches tall requires a permit. Des Moines' 12-inch frost depth means footings must bottom out below 12 inches — this is shallower than many regions but still demands below-frost-depth installation. Posts, ledger attachment (if attached), and railing height are inspected.
Fences
Fences over 6 feet, all masonry walls over 4 feet, and corner-lot sight-triangle fences require permits. Des Moines' small building department processes most fence permits over-the-counter in 1–2 days if you bring a completed application and site plan.
Residential additions and remodels
Any addition, room conversion, or structural remodel requires a building permit and plan review. The city will check roof load, wall bracing, window egress (if a bedroom), electrical, and plumbing updates. Plan review averages 2–3 weeks.
Roofs and siding
Roof replacement and exterior cladding require permits in Des Moines. Underlayment, flashing, and new-material specifications are checked. Siding work that involves structural sheathing or window replacement will trigger a full building permit; cosmetic paint or single-layer overlay may be exempt.
Electrical work
Anything beyond replacing outlets and switches requires an electrical subpermit. New circuits, EV chargers, panel upgrades, and solar installations all need a licensed electrician and inspection. Most DIY electrical is not permitted in Washington — hire a licensed contractor.
Plumbing and water heaters
Water heater replacement, new bathrooms, and drain/vent changes all require plumbing subpermits. The city processes these quickly if the applicant is a licensed plumber. DIY plumbing work is restricted — verify with the building department before self-permitting.
City of Des Moines Building Department
City of Des Moines Building Department
Contact City Hall at Des Moines, WA (verify address and current location when calling)
Search 'Des Moines WA building permit phone' or call City of Des Moines main line to be transferred to Building Department
Monday–Friday, 8 AM–5 PM (verify current hours before visiting)
Online permit portal →
Washington State context for Des Moines permits
Washington State adopted the 2018 International Building Code (IBC) and International Residential Code (IRC) with state-specific amendments. These amendments address Puget Sound marine conditions, including wind, rain exposure, and seismic hazards. Des Moines falls into seismic design category C, which means braced walls, foundation anchoring, and hold-down hardware are required for new construction and major remodels. The state also sets uniform energy-code requirements; new windows, doors, and insulation must meet current ENERGY STAR standards. Washington does not require a state-level building permit — all permitting is municipal. However, the state does regulate electrical work: only licensed electricians can pull electrical permits and perform new circuit installation. DIY electrical is severely restricted. Similarly, plumbing work over minor repairs requires a licensed plumber. Roofing and deck work can be owner-built if you pull the permit yourself, but you are responsible for all inspections and code compliance.
Common questions
Do I need a permit for a small deck or patio?
Yes, if it's over 30 inches tall. Des Moines requires a permit for any elevated deck or platform. The 12-inch frost depth means footings must extend below 12 inches — not the common 36-inch depth you see inland. If your deck is at grade (directly on the ground) and not attached to the house, it may be exempt, but call the building department first. Ledger-attached decks always need a permit because they involve house framing and water management.
Can I do my own electrical work or hire an unlicensed contractor?
No. Washington State law requires all electrical work to be performed by a licensed electrician. This includes new circuits, EV chargers, panel upgrades, and any work beyond outlet/switch replacement. The city will not issue an electrical permit to a homeowner for new work. Even if you own the house, you must hire a licensed electrician. The good news: electricians' labor costs are often less than you'd expect, and a licensed electrician pulls the permit and handles inspection — you don't have to.
How long does permit review take in Des Moines?
It depends on the project. Over-the-counter permits (fences, water heater swaps, simple electrical subpermits) often get approved same-day or within 1–2 business days. Full building permits for additions, remodels, or new construction typically take 2–4 weeks for initial plan review. If there are issues (missing calculations, unclear site plan, code conflicts), the city issues a request for information (RFI) and you resubmit. Budget an extra 1–2 weeks for revisions. The best move is to call the building department before you file — they'll tell you upfront if your plans are on track.
What happens if I skip the permit?
You're exposed to three major problems. First, unpermitted work often fails inspection during a home sale or refinance — the buyer's lender or title company discovers it and requires a remedial inspection or expensive correction. Second, if something goes wrong (a deck collapses, a fire starts from faulty wiring), your homeowner's insurance may deny the claim. Third, the city can issue a violation notice and force you to demolish or redo the work under permit. The cost of fixing unpermitted work is almost always more than the cost of doing it right the first time.
Am I allowed to be an owner-builder in Des Moines?
Yes. Washington allows owner-builders to pull permits for owner-occupied residential work. You must own and occupy the property. You are responsible for pulling the permit, submitting plans, paying fees, and arranging all inspections. You do not need to be licensed, but you must follow all building codes — the city inspector will check your work just as if a contractor had done it. Electrical and plumbing work are still restricted to licensed trades, even for owner-builders.
Do I need a site plan for my permit application?
Yes, for most projects. The site plan should show property lines, existing structures, your new project, setbacks from property lines, and any relevant features (trees, wetlands, water bodies, or sight triangles if you're in a corner lot). For small projects like a water heater swap, a simple sketch may suffice. For decks, additions, and fences, bring a dimensioned site plan (can be hand-drawn, but clear). The building department staff will tell you if your plan is complete.
How much does a permit cost in Des Moines?
Fees are based on construction valuation. A fence permit typically runs $75–$150. A deck or small addition costs $200–$800 depending on size and complexity. Electrical subpermits run $50–$150. Plan-check and inspection fees are bundled into the base permit fee — no surprise add-ons. Call the building department with your project scope and they'll give you a fee estimate.
What's the difference between the 12-inch frost depth in Des Moines and the 30+ inches in eastern Washington?
The Puget Sound region rarely freezes hard enough for frost heave at depth. The 12-inch frost depth is the point below which ground stays frozen most years — it's much shallower than eastern Washington or colder climates because the marine air keeps temperatures mild. This means deck footings, fence posts, and utility lines can be shallower in Des Moines. However, you still must go below 12 inches to be safe. If you're near the eastern edge of the city (toward Renton or the foothills), frost depth may be closer to 24–30 inches due to higher elevation — verify with the building department for your specific location.
Ready to file?
Call the City of Des Moines Building Department or visit City Hall to pick up an application. Bring your site plan (hand-drawn is fine), a brief description of the work, and an estimate of the project cost. The staff will tell you what else you need. Most simple projects can be complete over the counter in a single visit.