Mason County, Washington Building Permit Guide

In unincorporated Mason County, building, plumbing, mechanical and fire code permits come from Mason County Community Services: its Permit Assistance Center and Building/Planning Division at 615 W Alder Street, Shelton, 360-427-9670 ext. 352. You can apply on the SmartGov portal or book a submittal appointment. The county’s posted fee schedule starts at a $156 minimum and adds plan review at 65 percent of the permit fee.

What requires a building permit in Mason County?

The county’s document center lists the permit types it issues, and they go beyond new buildings: residential re-roofs, window replacements, garages and storage buildings, carports and decks, solar panels, demolition, a change of tenant in a commercial space, plumbing and mechanical work, floodplain development and land modification (grading). Freshwater piers and docks have their own replacement package, and manufactured homes their own placement permit.

Exempt work still has to meet the standards: the county’s guide notes that all grading, permitted or not, must follow Title 14.44, and that clearing before a critical area review is at the owner’s risk. Critical area violations can bring enforcement and triple permit fees.

What the county decides and what the state holds

Mason County’s current code page lists the 2021 International Building Code with appendices C, G, H and J, the 2021 Residential, Fire, Mechanical and Fuel Gas codes, the 2021 Uniform Plumbing Code and the Washington State Energy Code, all as adopted by the state. It also keeps the 1997 Uniform Code for the Abatement of Dangerous Buildings. Permit life and extensions follow a county policy under Mason County Code 14.08.040. Electrical permits are issued by the Department of Labor and Industries, not the county.

Mason County building department: who handles permitting

Mason County Community Services groups the Permit Assistance Center, the Building and Planning divisions, the fire marshal’s office and Environmental Health in one building. Planning, building and Environmental Health review a house application at the same time, and Public Works handles road access.

Shelton and the rest of the county

Mason County has one incorporated city. Inside it, the City of Shelton issues building permits through its own Community Development department and online permit portal; the county covers every other community, including the Allyn and Belfair urban growth areas.

Permit types and what comes first

Residential permits

The Before You Build guide sets out the house package: the building permit application and a plumbing/mechanical application, one site plan, three sets of construction drawings, two sets of engineering calculations and three geotechnical reports where required, the water adequacy application, the Washington State Energy Code form, a small parcel stormwater plan and a wetland delineation if one is needed. The site must already have septic approval or a sewer connection, and a site address. A planning pre-site inspection before design shows how much of the lot is free of buffers. Repeat designs can use the stock plan policy.

Building or remodeling a home here? Alliance handles residential permit filing, so the crew isn't waiting on the counter.

Commercial permits

Commercial projects use the Commercial Plan Submittal Checklist, the ADA checklist and a Special Inspection Agreement, and a pre-application meeting can be requested on its own application. New commercial buildings and remodels over 50 percent are valued from the ICC data for their occupancy; smaller remodels at half that. Fire code plan review adds 50 percent of the IBC plan review fee or $97 an hour.

For tenant improvements and new commercial builds, Alliance handles commercial permit expediting through issuance. More on this: commercial building permits explained.

What comes before the building permit

• Road access: an approved access permit from Mason County Public Works is needed before you apply when the lot is on a county road ($200 for a road approach/encroachment permit under Resolution 2025-055), and the driveway gets its own final inspection; WSDOT permits access to state highways.
• Septic: a licensed designer submits the onsite sewage application to Environmental Health, with test holes at least 5 feet deep and a 2-foot ramp for the inspector.
• Water: state law requires an adequate drinking water supply before a building permit is issued.
• Critical areas and shorelines: planners review shorelines, flood plains, streams, wetlands, habitat and landslide areas and may require a buffer; shoreline structures are valued at cost or fair market value under WAC 173-27-040.
• Fire access: a fire marshal site visit may be needed when a house is on a private road or more than 150 feet from a county-maintained road (Title 14.17).
• Burning: clearing debris burns need a burn permit outside the Allyn, Shelton and Belfair urban growth areas.

Mason County building permit fees

The fee schedule linked from the Building page values work from the International Code Council’s August building valuation data, switched over each September 1, and applies Table 1. Plan review (65 percent of the permit fee, or $97 an hour with a one-hour minimum where no other rate applies) and the addressing and other review fees are collected at submittal; the permit fee is collected at issuance. The schedule adds a technology fee under Mason County Ordinance 84.17, and in its own words the “State Building Fee collected per RCW 19.27.085.” The commissioners adopted this schedule by Ordinance 2024-045 on August 13, 2024. Public Works adds its own charges under Resolution 2025-055 of September 16, 2025.

Worked example: a house valued at $300,000 falls in the $100,001 to $500,000 band: $1,093.12 plus 200 × $6.16 = $2,325.12 for the permit, with 65 percent plan review and 5 percent energy code review on top, plus the $100 Public Works development review fee, the technology fee, state fee and trade permits. A project that adds trips in the Belfair area also pays the Belfair traffic mitigation fee ($1,276.28 per trip in 2026). The top band does not chain from the one below (the $500,001 band reaches $6,167.12 at $1,000,000, against $6,166.35 printed), so keep estimates inside one band. The county’s online estimator gives residential estimates only.

The same schedule prices a foundation-only permit at 20 percent of the project’s total valuation (minimum $156), a commercial re-roof or tank job at no less than $190 and a commercial change of tenant at $156 plus any fire and building plan check. An in-ground pool or built-in spa starts at $156, an above-ground pool over 5,000 gallons is $62.50, and the pool barrier inspection that state law can require is $48.50. Appeals of administrative decisions cost $660.

Trade permits and who may pull them

Plumbing and mechanical work is permitted by the county on one Plumbing / Mechanical application. A new single-family plumbing system is a flat fee by house size ($182 up to 1,499 sq ft, rising to $307 plus $100 over 6,000 sq ft), and other work is $10 a fixture plus the $30 issuance fee. Electrical work is inspected by L&I, and the county’s guide requires the electrical rough-in to be approved before you call for the framing inspection.

• Contractors: the Before You Build guide asks for the builder’s name and state contractor number on the application form, so have the registration in hand before you file.

How to apply for a Mason County building permit

Review, corrections and what causes delay

Planning, building and Environmental Health review at the same time, and a reviewer who needs more information contacts you or your agent directly with a list. Environmental Health checks that the approved septic plot plan matches the building site plan and that water adequacy is met, and planners check critical area buffers, so differences there come back as requests. A permit stays valid for 180 days from the last inspection, so an inspection at least every 180 days keeps it alive; extensions follow the county’s written policy.

Inspections

You can leave a message on the inspection line, call staff, ask in person or use the portal; the permit must be issued, valid and paid. Requests received before 3 p.m. are confirmed the same business day and routed to the next available date. Inspections run between 9 a.m. and 4 p.m. on weekdays, without set appointment times, and different parts of the county are covered on different days, so the county suggests asking 3 to 5 business days ahead. Cancel before 9 a.m. to avoid a re-inspection fee. Inspectors are typically in the office from 8 to 9 a.m.

The Before You Build guide spells out the timing. The foundation wall inspection comes after forms, reinforcement (for walls over 2 feet unless the engineer says otherwise), foundation vents and access openings are in, before any concrete. The framing, plumbing and mechanical inspection waits until the roof, framing, fire blocking, windows, chimneys, siding and bracing are done, plumbing lines are under water or air test, and L&I has approved the wiring for cover.

A site-built house usually has at least five inspections: footing and setback, foundation wall, framing with plumbing and mechanical, insulation, and final, with slab, shear wall and gypsum board checks where they apply. The final needs the septic as-built approved and the address posted. Once the final is signed, the green inspection card serves as the certificate of occupancy.

Washington building code and flood maps

Mason County administers the 2021 Washington codes listed on its current code page. FEMA’s Community Status Book shows both Mason County and the City of Shelton as participating communities in the National Flood Insurance Program; floodplain work outside Shelton needs the county’s floodplain development permit.

Washington has a mandatory statewide building code under chapter 19.27 RCW that every city and county enforces and may make stricter; electrical permits come from the Department of Labor and Industries unless the city runs its own program or Tacoma Power serves the site. Building codes in Washington

Mason County building permit FAQ

Do I need an appointment to apply?

Only to submit in person. Online applications on SmartGov need no appointment, and you can call or drop in with questions.

How much is a building permit for a $300,000 house?

$2,325.12 for the permit on Table 1, plus 65 percent plan review, energy review, the $100 Public Works development review fee and the state and technology fees.

Does replacing my roof need a permit?

Yes. A residential re-roof is a $131 flat-fee permit.

How long is a permit good for?

180 days from the last inspection; keep inspections going to keep it active.

Who inspects the wiring?

Labor and Industries, and its approval is needed before the county’s framing inspection.

Does the county issue permits in Shelton?

No. The City of Shelton issues its own; the county covers the rest of Mason County.

Permit search and official resources

Permit status and records are searchable on the county’s SmartGov portal. For older plans and permits, use the county’s public records request portal; Environmental Health keeps septic permit records (360-427-9670 ext. 400).

• Mason County Building Division and document center
• Mason County SmartGov permit portal
• Permit submittal appointment booking
• Building permit fee schedule and valuation table
• Before You Build guide
• Building inspections FAQ
• Current adopted codes
• Permit expiration and extension policy
• 2026 county office hours
• Environmental Health (septic)
• Shoreline Master Program
• City of Shelton building permits
• L&I city electrical inspection list
• L&I contractor registration
• FEMA Community Status Book, Washington

Simplify Mason County permitting with Alliance Permitting

Alliance Permitting is a permit documentation and submission company in Washington. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.

This guide is provided by Alliance Permitting for general information about Mason County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.