City of Issaquah building permits: fees, timelines & requirements (2026)
Every fee, threshold, and review window for City of Issaquah permits — cited to the city's own page and re-verified weekly. 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 · 17 typically require a permit · 4 often do not.
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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 | Yes | 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: $4.50 per building permit. Trade permits separate. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Bathroom remodel | Yes | 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. | — | Cite verified 2026-06-26 |
| Basement finish | Yes | 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 $4.50. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Deck | Yes | 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 2026-06-26 |
| Fence | Often no | Fences are exempt up to 6 feet (Tip Sheet 0); a permit is required over 6 feet, in a critical area, or for a fence with an additional 2 feet of lattice on top. Maximum height is 4 feet in the front setback and 6 feet in side/rear setbacks. | Typically no fee unless permit required. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Siding | Often no | 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. | — | Cite verified 2026-06-26 |
| Window replacement | Often no | 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. | — | Cite verified 2026-06-26 |
| Flooring | Often no | Interior finish work (carpet, tile) is exempt — no permit required. | No permit fee for surface flooring. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| ADU / DADU | Yes | 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 $4.50/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 2026-06-26 |
| Roofing | Yes | 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. Typically $150-$400 for residential. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| HVAC | Yes | 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. The mechanical permit fee is 8% of the building permit fee. | Mechanical permit + electrical permit (if new circuit) + plumbing permit (if condensate to drain). Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Electrical | Yes | 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. | L&I permit fees by circuit count + service size. Standard residential ~$60-$200. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Plumbing | Yes | 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 by fixture count. Standard residential ~$80-$250. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-06-26 |
| Addition | Yes | 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 $4.50 per building permit. Trade permits (E/P/M) separate. Apply via https://mybuildingpermit.com. | 45–120 days | Cite verified 2026-06-26 |
Ancillary & non-building permits
| Project | Permit? | Threshold | Fee | Review days | Source |
|---|---|---|---|---|---|
| Demolition | Yes | 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 $4.50 applies. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Right-of-way | Yes | 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. | ROW permit fees vary widely by city; commonly $150-$500 for residential driveway/curb cut, plus per-day occupancy if street obstruction. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Side sewer | Yes | Side-sewer permits issued by the local utility (Seattle SPU; King County WTD; per-city utility elsewhere) under 2021 UPC + city utility code. Triggered by new connection, repair >2 ft of pipe, relining (CIPP), or capping at the property line for demolition. | Side-sewer permits typically $150-$500; depth-based surcharge in some cities. Utility-issued, not building-permit-issued. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Stormwater / drainage | Yes | KC Surface Water Design Manual 2021 (KCC 9.04 + adopted by reference in most KC cities) sets the 2,000 sqft new+replaced impervious threshold for "small project" drainage review; ≥5,000 sqft triggers full drainage review. Different thresholds in critical-area drainage basins. | Drainage review fee commonly tiered by project size; small project ~$300-$800, full drainage review $1,500+. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Land-use / zoning | Yes | 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; variance commonly $1,000-$3,000 + actual cost recovery for hearing examiner. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Tree removal | Yes | Triggered by removal of trees meeting the city's "significant tree" / "exceptional tree" / "tier" threshold. Common thresholds: ≥6in DBH (Bellevue tier 2+), ≥24in DBH (Seattle exceptional), or specific listed species. Single-family lots are sometimes exempt for non-exceptional trees. | Tree-removal permits commonly $50-$300 per tree; replacement bonds in some cities. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Signs | Yes | 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 commonly $100-$400 plus electrical sub-permit. Apply via https://mybuildingpermit.com. | — | Cite verified 2026-05-16 |
| Other / general | Pending verification | — | — | — | — |
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.