City of Issaquah building permits: fees, timelines & requirements (2026)
What needs a permit in City of Issaquah and what triggers one — each row quoted from the city's own code or permit page, with the source linked and the source page checked daily for changes. Fees and review times appear where the city publishes them. Covers ADU, addition, kitchen, bathroom, basement, deck, fence, siding, windows, flooring, roofing, HVAC, electrical, plumbing, and ancillary permits (King County).
21 of 24 project types have authoritative rules on file · 13 always require a permit · 9 depend on the scope · 1 do not.
Get your lot in 3D with zoning, setbacks, and the exact permits your project needs — cited to City of Issaquah's source.
Permit department
Community Planning & Development
Adopted code cycles
2021 IRC w/ WA amendments · 2021 WSEC
Resources
Construction permits
| Project | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
| Kitchen remodel | Depends on scope | No permit for cabinets, counters, paint or tile. A permit once you move plumbing, add circuits, run gas or change walls. A Single-Family Interior Remodel permit is required for all interior remodels. Sink/toilet replacement without plumbing-line modification is exempt; cabinets/countertops/tiling are exempt finish work; any plumbing/mechanical fixture alteration or structural change triggers the permit. | Fees set by jurisdiction. WA Building Code Council surcharge: $6.50 per building permit. Trade permits separate. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Bathroom remodel | Depends on scope | No permit for tile, paint or a same-spot fixture swap. A permit once plumbing moves, circuits are added or the tub or shower goes. Tub and shower replacement requires a permit; sink/toilet replacement without plumbing-line modification is exempt. Processed under the Single-Family Interior Remodel permit. | Fees set by jurisdiction. Plus separate electrical, plumbing, and mechanical permits. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Basement finish | Always | Finishing a basement into habitable space needs a building permit; egress and ceiling height are the usual review items. Finishing or remodeling a basement is processed under the Single-Family Interior Remodel permit; no basement-specific square-footage exemption is published. | Plan-review fee scales with valuation. State surcharge $6.50. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Deck | Depends on scope | A deck 30 in or under above grade needs no permit; above 30 in, any new, repair or modification work does. A permit is required before any repairs, additions, or modifications to a deck more than 30 inches above grade (measured to the lowest point within 6 feet of the deck). Setbacks per IMC 18.404 by zone; decks in mapped ECA areas trigger critical-area review. | Most jurisdictions handle decks as field-inspection or simplified plan review. Apply via https://mybuildingpermit.com. | 14–28 days | Cite verified 2026-09-24 |
| Fence | Depends on scope | No permit for a fence 6 ft or under outside a critical area. Residential fences do not require a building permit unless the fence is more than 6 feet in height or is in a critical area. Separately from the permit trigger, the maximum height in the front setback is 4 feet in the Single-Family/Duplex (SF-D) zone per IMC 18.700.160; other land-use restrictions may apply (IMC 18.600.090), and HOA approval may be required. | Typically no fee unless permit required. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Siding | Depends on scope | Non-structural siding is exempt; EIFS, veneer or stucco needs a permit. Non-structural siding replacement is exempt, except for EFIS (exterior finish and insulation systems), veneer, or stucco, which require a permit. | Typically minimal fee — like-for-like usually exempt. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Window replacement | Depends on scope | Like-for-like is exempt when the opening is unchanged, efficiency is not reduced and egress is kept. A new or larger opening needs a permit. Like-for-like window/door replacement is exempt when the opening is not increased, energy efficiency (U-value) is not decreased, and egress is maintained. A new or larger opening requires a permit. | Like-for-like usually no permit fee. Structural changes scale with valuation. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Flooring | No permit | Flooring is interior finish work and exempt. Interior finish work (carpet, tile) is exempt — no permit required. | No permit fee for surface flooring. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| ADU / DADU | Always | An ADU or DADU always needs a building permit, and usually trade permits with it. IMC 18.500.090: ADU max 1,000 sq ft GFA excluding non-living areas (garage, storage sheds, decks) — except when the excluded area IS the location of the proposed ADU. Principal unit GFA must be ≥25% greater than largest ADU on the lot. Up to TWO ADUs per lot (any combination attached/detached) allowed alongside the primary residence. Owner- occupancy NOT required (preempted by WA HB 1337). New ADUs not subject to rear-yard setback when rear abuts a public alley (unless the city plows that alley). 4-ft walkway required from ROW/driveway to ADU primary entrance. Height per IMC 18.404 form-and-intensity for the underlying zone (typically 30 ft in SF-D / SF-S / SF-SL). Parking: one additional off-street stall required per Issaquah ADU site-plan rules (may be waived for ADUs within ½ mi of frequent transit per HB 1337). | Building permit fee is valuation-based (Issaquah adopts UBC Table 1-A bracket schedule). Plan review fee 65% of building fee. WA state BCC surcharge $6.50/unit. Application fees invoiced via https://mybuildingpermit.com; 3% credit-card service fee or pay by check / exact cash. Impact fees apply on top of permit fee: traffic concurrency, school, parks. HB 1337 caps ADU impact fees at 50% of single-family unit rate — confirm Issaquah's current adopted ADU schedule at fee schedule URL. King County sewer capacity charge (~$8k-$10k) applies separately if ADU is on the King County sewer system. | 45–120 days | Cite verified 2026-05-16 |
| Roofing | Depends on scope | In-kind re-roof without sheathing change, overlays up to two layers, and repairs under 100 sq ft are exempt. Sheathing, skylights, a pitch change, mechanical units or a covering more than 10 lb per sq ft heavier needs a permit. A permit is required for a re-roof involving structural elements — sheathing, skylights, change of roof pitch, adding/relocating mechanical units, or a roof-material change exceeding 10 lb/sq ft. In-kind re-roof without sheathing change, overlays ≤2 layers, and repairs <100 sq ft are exempt. | Flat fee or valuation-based, per the city's fee schedule. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| HVAC | Always | Furnaces, AC, heat pumps, gas appliances and gas piping need a mechanical permit. A mechanical permit is required for furnaces, AC, heat pumps, gas appliances and gas piping. Mechanical work tied to a building permit is a component of it; standalone fixtures issue online. For one- and two-family dwellings the fee is 8% of the determined building permit fee for NEW CONSTRUCTION only. For remodels, additions and anything other than new construction it is a flat $62.88 per new appliance, per duct system, or for gas piping alone, with a $62.88 minimum and a $422.04 maximum; a like-for-like water heater or furnace replacement is $62.88. A separate technology fee applies. Commercial and multifamily are charged on valuation instead (Table C-2). | Issaquah Mechanical Fee Schedule, Table C-1 (one- and two-family) and Table C-2 (commercial / multifamily): https://www.issaquahwa.gov/DocumentCenter/View/549 — the Mechanical Permits page itself publishes no rates and links this schedule. | Not published by the city | Cite verified 2026-09-24 |
| Electrical | Always | Electrical work needs a permit, issued by WA L&I rather than the City. Electrical work requires a permit, but in Issaquah electrical permits are reviewed and issued by the Washington State Department of Labor & Industries, not the City. | Electrical permit fees are set by circuit count and service size in the issuing agency's fee schedule. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Plumbing | Depends on scope | Fixtures, lines, an electric water heater or an irrigation backflow device need a plumbing permit. A plumbing permit is required for fixtures/lines, electric water-heater installs, and irrigation backflow devices (a separate over-the-counter plumbing permit is required before the work). The plumbing permit fee is 8% of the building permit fee. | Plumbing permit fees are set by fixture count in the city's fee schedule. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Addition | Always | Adding floor area always needs a building permit. A permit is required for all single-family/duplex new construction and additions; no exemption is published. Setback / form / intensity per IMC 18.404. | Plan-review fee scales with valuation per UBC Table 1-A. State surcharge $6.50 per building permit. Trade permits (E/P/M) separate. Apply via https://mybuildingpermit.com. | 45–120 days | Cite verified 2026-09-24 |
Ancillary & non-building permits
| Project | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
| Demolition | Always | Demolishing a structure or a substantial part of one needs a permit; asbestos and lead notifications are separate. 2021 IBC Section 105.1 + WA-adopted IRC R105.1: demolition of any structure or portion thereof requires a permit. Tear-out of interior finishes only is generally treated as alteration. Asbestos / lead notification often required separately under WAC 173-303 / 296-62. | Demolition fees commonly charged as flat fee or by structure size. State surcharge $6.50 applies. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-05-16 |
| Right-of-way | Always | Any work in or occupation of the public right of way needs a right-of-way permit from public works. Issued by city public works (or SDOT in Seattle) under local ROW ordinance. Triggered by physical occupation of or work within the public ROW including driveway aprons, curb cuts, sidewalk replacement, utility tie-ins, hauling routes, and temporary construction staging. | Right-of-way permit fees vary by city: a base fee for a residential driveway or curb cut, plus a per-day occupancy charge if the street is obstructed. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-24 |
| Side sewer | Always | A new side-sewer connection, a repair beyond about 2 ft, relining or capping needs a permit from whichever utility owns the main. The side-sewer permit is issued by whichever utility owns the sanitary sewer — the city, a sewer or water district, or a regional utility — under that utility's own code, with WAC 51-56 (2021 UPC) governing how the building sewer is laid. WHICH UTILITY IS A PER-PROPERTY FACT: a lot can sit inside a city for permitting and outside its sewer district, so confirm the owner of the main before applying. Triggered by a new connection, repair of more than about 2 ft of pipe, relining (CIPP), or capping at the property line for a demolition. | Side-sewer permit fees are set by the utility that owns the main; some add a depth-based surcharge. Utility-issued, not building-permit-issued. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-06 |
| Stormwater / drainage | Always | New or replaced impervious surface and land disturbance are reviewed under the drainage manual this jurisdiction adopts; the threshold is the manual's. Ecology's Stormwater Management Manual for Western Washington (SWMMWW, 2024 edition) is the state floor. A municipal stormwater permittee may instead adopt a REGIONAL manual Ecology has determined equivalent, and most do — some counties publish their own, some cities publish their own, and others adopt Ecology's directly. WHICH MANUAL APPLIES IS A PER-JURISDICTION FACT and it changes the numbers: review thresholds for new plus replaced impervious surface and for land-disturbing activity differ between manuals, so read this jurisdiction's own adopting chapter before quoting one. Critical-area and closed-basin parcels get stricter review under every manual. | Drainage review fees are commonly tiered by project size in the city's fee schedule. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-06 |
| Land-use / zoning | Always | A variance, conditional use, plat or design review is a land-use decision that precedes the building permit. Triggered when a project does not conform to the strict letter of the zoning code. Variances require a hardship finding under most city codes. Design review thresholds vary (Seattle: most multifamily + non-residential >4,000 sqft; many cities: design review only in designated districts). | Land-use fees vary widely; a variance usually carries an application fee plus cost recovery for the hearing examiner. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-05-16 |
| Tree removal | Depends on scope | A Tree Permit is required to remove a significant tree: 6 in DBH or greater, 8 in for alder and cottonwood, measured 4.5 ft above grade. A Tree Permit is required in most cases for removal, excessive pruning (IMC 18.102.090), and creating a wildlife snag. A significant tree is 6" DBH or greater, or 8" DBH or greater for alder and cottonwood; DBH is measured 4.5 feet above average grade. The most common exemption is removal of nonsignificant trees not protected by any other means. Replacement is required at not less than 1:1 and must provide canopy coverage equal to or greater than the tree(s) removed (IMC 18.812.060) — waivable if the site still meets canopy targets after removal. | Fee assessed at time of permit application per IMC 3.64.010; a decision may not be made until fees are paid. No fee applies when all trees proposed for removal are deemed hazardous. | Not published by the city | Cite verified 2026-09-24 |
| Signs | Always | Permanent signs need a sign permit; small temporary residential signs are usually exempt. City sign code (typically Title 22 or 23) governs. Wall, freestanding, projecting, awning, and electronic message signs all require permits. Most cities exempt small temporary residential signs (real-estate, political) under area thresholds (~6 sqft). | Sign permit fees are set in the city's fee schedule, plus an electrical sub-permit for an illuminated sign. Apply via https://mybuildingpermit.com. | Not published by the city | Cite verified 2026-09-06 |
Building in City of Issaquah?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, bonded and insured — working throughout City of Issaquah and King County. We pull the permits listed above and build the project.
How this page is built
Each row is the most-recently-verified authoritative rule on file for City of Issaquah and the listed project type. “Pending verification” means we have City of Issaquah in our database but haven't yet personally checked the city page for that project — those rows fall back to King-County or Washington-state baselines until verified.
See the data-quality leaderboard for how we keep these current, or run an address-specific lookup on the main permits page.