Building permits in Whatcom County, Washington
Find the right authority before you build. Whatcom County permitting follows Washington law — here is exactly who issues the permit and where to start.
County + cities (mixed)
Whatcom County Planning & Development Services — Building Services Division (unincorporated areas)
Whatcom County PDS Building Services reviews, processes, and inspects building permits for the unincorporated county, submitted by email to [email protected]. Bellingham, Ferndale, Lynden, Blaine, and other incorporated cities issue their own permits.
Check a home project's permit in Whatcom County, Washington
Select a project to see its Washington permit rule. Whether the county or your city issues it depends on incorporation status — see the authority note above.
Washington
Exact permit fees are set by the local building department. WikEst shows the published or code-based range where one exists, linked to its official source — verify the final amount at the source before budgeting.
🏠 Accessory Dwelling Unit (ADU) permit fee in Washington
Permit requiredGenerally allowedcity authority
Permit fee range
Valuation-based; Seattle SDCI issue fees scale with project value (no flat state fee).
Typical timeline
Seattle pre-approved DADU plans ~2–6 weeks; custom plans longer.
Setback
Seattle: 5 ft rear (0 ft where lot abuts an alley); varies by city/zone.
Exempt if
Statewide HB 1337 (eff. 2025) allows ≥1 ADU per lot; Seattle allows up to 2 ADUs.
Exempt criteria: None — a building permit is always required for an ADU.
Washington HB 1337 (2025) mandates ADUs; Seattle also allows two ADUs per lot. Owner-occupancy and extra parking are not required in Seattle.
Official sources: Seattle SDCI — Accessory Dwelling Units · WA State Building Code Council — 2021 IRC (WAC 51-51)
Representative cities for Washington: Seattle, Spokane.
All 20 project fee ranges in Washington
Official-source ranges where published; “By local jurisdiction” means no flat fee is published and the amount is set case by case.
| Project | Permit? | Authority | Fee range | Go / no-go |
|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | yes | city | Valuation-based; Seattle SDCI issue fees scale with project value (no flat state fee). | allowed |
| 🪵 Deck / Porch | conditional | city | Valuation-based; fee set by the issuing city. | allowed |
| 🧱 Fence / Wall | conditional | city | Often no building-permit fee when under the height threshold; zoning rules still apply. | allowed |
| 🛖 Shed / Outbuilding | conditional | city | Valuation-based when a permit is required; many small sheds are exempt. | allowed |
| 🪜 Basement Finish | yes | city | Valuation-based; includes trade permits (electrical, plumbing). | allowed |
| 🚗 Garage / Carport | yes | city | Valuation-based; includes trade permits. | allowed |
| ☀️ Rooftop Solar PV | yes | city | Building + electrical permits; Seattle combined fees typically a few hundred dollars. | allowed |
| 🌡️ HVAC Replacement | yes | city | Mechanical (trade) permit; fee set by city. | allowed |
| 🍳 Kitchen Remodel | conditional | city | Valuation-based when structural/plumbing/electrical work is included. | allowed |
| 🛁 Bathroom Remodel | conditional | city | Valuation-based when plumbing is relocated. | allowed |
| 🏗️ Room Addition | yes | city | Valuation-based; includes trade permits. | allowed |
| 🪟 Window / Door Replacement | conditional | city | Usually no fee for in-kind swap; permit needed if opening is enlarged. | allowed |
| 🏘️ Roof Replacement | conditional | city | Often Subject-to-Field-Inspection or exempt for same-footprint re-roof. | allowed |
| 🅿️ Driveway / Parking Pad | conditional | city | Building permit often not required; curb-cut/right-of-way work is separate. | allowed |
| 🏊 Swimming Pool / Spa | yes | city | Valuation-based; includes barrier/fencing review. | allowed |
| 🧱 Retaining Wall | conditional | city | Valuation-based when over the height threshold. | allowed |
| 💥 Demolition / Teardown | yes | city | Demolition permit fee set by the city; verify locally. | allowed |
| 🚰 Septic System | yes | county | Onsite sewage permit fee set by the local health jurisdiction; verify locally. | allowed |
| 🔌 EV Charger | conditional | city | Electrical permit fee set by the city; verify locally. | allowed |
| ⚡ Standby Generator | yes | city | Electrical (and often mechanical/gas) permit fee set by the city; verify locally. | allowed |
Permit cheat-sheet (Washington rules)
| Project | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | Permit required | city | Valuation-based; Seattle SDCI issue fees scale with project value (no flat state fee). | Seattle pre-approved DADU plans ~2–6 weeks; custom plans longer. | Generally allowed | Washington HB 1337 (2025) mandates ADUs; Seattle also allows two ADUs per lot. Owner-occupancy and extra parking are not required in Seattle. Exempt: Statewide HB 1337 (eff. 2025) allows ≥1 ADU per lot; Seattle allows up to 2 ADUs. |
| 🪵 Deck / Porch | Conditional | city | Valuation-based; fee set by the issuing city. | Simple decks may be Subject-to-Field-Inspection; standard review 4–8 weeks. | Generally allowed | Attached decks and decks over 30 in above grade always require a permit. Exempt: Freestanding decks ≤30 in above grade and ≤200 sq ft are commonly exempt. |
| 🧱 Fence / Wall | Conditional | city | Often no building-permit fee when under the height threshold; zoning rules still apply. | Typically no building permit below threshold; review only if over height. | Generally allowed | Corner lots have sight-triangle limits; Environmentally Critical Area (ECA) lots need a pre-application site visit. Exempt: Seattle: no building permit for fences < 8 ft; Spokane generally requires a permit for new/replacement fences. |
| 🛖 Shed / Outbuilding | Conditional | city | Valuation-based when a permit is required; many small sheds are exempt. | Exempt sheds need no review; others often Subject-to-Field-Inspection. | Generally allowed | Lot-coverage and stormwater rules still apply even when a permit is not required. Exempt: Seattle: one-story detached accessory building <120 sq ft roof area on slab-on-grade exempt; Spokane <200 sq ft exempt. |
| 🪜 Basement Finish | Permit required | city | Valuation-based; includes trade permits (electrical, plumbing). | Standard review 4–8 weeks. | Generally allowed | Bedrooms must have an emergency egress window (≥5.7 sq ft opening). Exempt: Cosmetic-only finishing (paint, flooring) is exempt. |
| 🚗 Garage / Carport | Permit required | city | Valuation-based; includes trade permits. | New structure review; complex projects 8–16 weeks. | Generally allowed | Attached and detached garages require a full building permit and plan review. Exempt: No exemption — a new garage is a new structure. |
| ☀️ Rooftop Solar PV | Permit required | city | Building + electrical permits; Seattle combined fees typically a few hundred dollars. | Seattle Solar Express: same-day for standard residential PV <30 kW (RCW 64.40 / HB 1117). | Generally allowed | Washington HB 1117 requires expedited solar permitting; HOA solar restrictions are limited by RCW 64.38.055. Exempt: No size exemption; systems >30 kW use the standard path. |
| 🌡️ HVAC Replacement | Permit required | city | Mechanical (trade) permit; fee set by city. | Trade permits often issued quickly; same-day in many cases. | Generally allowed | New equipment must meet the Washington State Energy Code (WSEC-R). Exempt: No exemption for equipment replacement. |
| 🍳 Kitchen Remodel | Conditional | city | Valuation-based when structural/plumbing/electrical work is included. | Standard review 4–8 weeks for permitted scopes. | Generally allowed | Verify whether walls are load-bearing before any layout change. Exempt: Cabinet/countertop swap in the same layout is exempt. |
| 🛁 Bathroom Remodel | Conditional | city | Valuation-based when plumbing is relocated. | Standard review for permitted scopes. | Generally allowed | Ventilation must meet code; exhaust to the exterior is required. Exempt: Fixture-for-fixture swap in place is often exempt. |
| 🏗️ Room Addition | Permit required | city | Valuation-based; includes trade permits. | Complex review 8–16 weeks. | Generally allowed | Middle-housing reforms (HB 1110) may allow more units by right; check zoning. Exempt: No exemption — any new conditioned footprint requires a permit. |
| 🪟 Window / Door Replacement | Conditional | city | Usually no fee for in-kind swap; permit needed if opening is enlarged. | In-kind swaps typically need no review. | Generally allowed | Replacement windows should meet U-factor requirements when the energy code is triggered. Exempt: Same-size, in-kind replacement is generally exempt. |
| 🏘️ Roof Replacement | Conditional | city | Often Subject-to-Field-Inspection or exempt for same-footprint re-roof. | STFI re-roofs can be approved same-day. | Generally allowed | Snow-load and seismic detailing apply in eastern WA (Spokane). Exempt: Same-material, same-slope re-roof often exempt/STFI. |
| 🅿️ Driveway / Parking Pad | Conditional | city | Building permit often not required; curb-cut/right-of-way work is separate. | Right-of-way permits reviewed by the city/utility. | Generally allowed | A separate right-of-way or utility permit is usually needed to cut the curb. Exempt: Seattle: driveways <18 in above grade exempt from building permit; Spokane <30 in exempt. |
| 🏊 Swimming Pool / Spa | Permit required | city | Valuation-based; includes barrier/fencing review. | Standard review; varies by city. | Generally allowed | Washington adopts the International Swimming Pool & Spa Code (WAC 51-50-3109); barrier fencing is mandatory. Exempt: No exemption — pools/spas require a permit (incl. most above-ground). |
| 🧱 Retaining Wall | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in Environmentally Critical Areas need a pre-application site visit. Exempt: Walls <4 ft from bottom of footing are generally exempt. |
| 💥 Demolition / Teardown | Permit required | city | Demolition permit fee set by the city; verify locally. | — | Generally allowed | A full teardown or major structural demolition requires a demolition (building) permit from the city under the Washington State Building Code (WAC 51-51). Structures built before 1978 may require an asbestos/lead-paint survey and abatement, and utility disconnects are typically required before teardown. Interior non-structural strip-out may be exempt. |
| 🚰 Septic System | Permit required | county | Onsite sewage permit fee set by the local health jurisdiction; verify locally. | — | Generally allowed | Onsite sewage (septic) systems are permitted by the local health jurisdiction (county health department) under Chapter 246-272A WAC, administered by the Washington State Department of Health. A site evaluation and design are required; larger or alternative systems need a licensed designer. |
| 🔌 EV Charger | Conditional | city | Electrical permit fee set by the city; verify locally. | — | Generally allowed | A home EV charging station normally requires an electrical permit for a dedicated 240V circuit and wall unit, issued by the city under the Washington State Building Code / NEC. Plug-in (cord-and-plug) Level 1 charging from an existing outlet may be exempt where code allows; a new dedicated circuit or hardwired unit requires a permit. |
| ⚡ Standby Generator | Permit required | city | Electrical (and often mechanical/gas) permit fee set by the city; verify locally. | — | Generally allowed | A permanently installed standby generator with a transfer switch and fuel (natural gas/propane) line requires electrical and often mechanical/gas permits, plus inspection (NEC Art. 445/702 context). Setback, noise, and carbon-monoxide rules may apply, and HOAs may restrict installation. Verify with the city building department. |
Frequently asked questions
Who issues building permits in Whatcom County, Washington?
Whatcom County Planning & Development Services — Building Services Division (unincorporated areas) is the permitting authority for Whatcom County. Permitting is split — cities issue for incorporated areas, the county for unincorporated areas. Start at the official portal linked above.
Do I go to the county or my city for a building permit in Whatcom County?
Permitting is split — cities issue for incorporated areas, the county for unincorporated areas.
What home projects need a permit in Whatcom County?
The same project types shown in the cheat-sheet above (ADU, deck, fence, shed, solar, and more) — rules follow Washington state law. Whether the county or your city issues it depends on your property's incorporation status.
How do I apply for a permit in Whatcom County?
Use the official permit portal linked above. Most offices accept online submissions; have your plans, site information, and contractor details ready before applying.