Cowlitz County
Building Permit Cost Calculator
Cowlitz County charges for a building permit based on the valuation of the work — not a flat fee. Here's what that actually comes to.
Project valuation
The value of the permitted work — materials and labor. Not your whole project if only part of it needs a permit.
Estimated total at common valuations
Small deck, $8,000 valuation: estimated total $483.81. Plan review $165.97 plus $62.50 in add-on fees due when you submit plans ($228.47), then the $255.34 building permit fee due when the permit is issued. $497.12 if you pay by card (2.75% service fee).
Deck rebuild, $15,000 valuation: estimated total $754.20. Plan review $272.49 plus $62.50 in add-on fees due when you submit plans ($334.99), then the $419.21 building permit fee due when the permit is issued. $774.94 if you pay by card (2.75% service fee).
Patio cover, $7,000 valuation: estimated total $445.18. Plan review $150.75 plus $62.50 in add-on fees due when you submit plans ($213.25), then the $231.93 building permit fee due when the permit is issued. $457.43 if you pay by card (2.75% service fee).
Large deck, $35,000 valuation: estimated total $1,416.51. Plan review $533.40 plus $62.50 in add-on fees due when you submit plans ($595.90), then the $820.61 building permit fee due when the permit is issued. $1,455.46 if you pay by card (2.75% service fee).
Garage, $60,000 valuation: estimated total $2,024.61. Plan review $772.95 plus $62.50 in add-on fees due when you submit plans ($835.45), then the $1,189.16 building permit fee due when the permit is issued. $2,080.29 if you pay by card (2.75% service fee).
Addition, $120,000 valuation: estimated total $3,110.64. Plan review $1,200.78 plus $62.50 in add-on fees due when you submit plans ($1,263.28), then the $1,847.36 building permit fee due when the permit is issued. $3,196.19 if you pay by card (2.75% service fee).
This covers unincorporated Cowlitz County
If your property is inside the city limits of Kalama, Longview, Kelso, Castle Rock or Woodland, that city runs its own fee schedule and the number will be different. Not sure which one you're in? That's worth a phone call before you apply — I've watched an application get rejected and rerouted over exactly this.
How Cowlitz County actually charges for a permit
There's no flat fee. The county assesses the building permit fee from Table A-1 based on the valuation of the work, then charges a plan review fee equal to 65% of that permit fee. Those two are the bulk of it. A $46 permit administration fee, a $10 technology fee, and a $6.50 state Building Code Council fee get added on top.
The two big fees land at different times. Plan review is collected when you turn in your application and drawings. The building permit fee comes due when the permit is actually issued. So the first check you write is roughly a third of the total, and people are often surprised by the second one.
What counts as "valuation"
For an alteration or a repair, valuation is the fair market value of the work — materials plus labor for the permitted scope only. If you're rebuilding a deck on a property where you're also doing landscaping and a driveway, only the deck value goes on the permit application.
For new construction the county can instead compute valuation from square footage using ICC Building Valuation Data, and for decks, porches and patio covers that's assessed at half the utility building rate. That can land in a different place than your contract price, so treat this calculator as a close estimate for alterations and a ballpark for new builds.
Do you even need a permit?
Replacing decking boards like-for-like generally doesn't require one. Guardrail work on a deck more than 30 inches above grade does, under IRC R312. New structures, additions, and anything structural need one. When it's genuinely unclear, the county permit technician will tell you straight — 360-577-3052.
You'll need a drawing before you can apply
The county won't take a permit application without one. I'll sketch your project free — no obligation.
Questions about a permit on your project?
(360) 431-9382.
Estimate only, based on the Cowlitz County Building Division 2026 adopted fee schedule effective July 1, 2026. Actual fees are set by the county and may include planning, environmental, health department, impact or school fees not shown here. Confirm with the Cowlitz County permit technician before you budget.