What happens if you skip the permit (and you needed one)
- Stop-work orders and fines: Edmonds Building Department issues citations up to $500–$1,000 per day of unpermitted work, plus mandatory permit fee recalculation.
- Insurance claim denial: ADU not disclosed to insurer can void coverage for damage or liability on the unit; lenders will demand removal before refinance.
- Resale disclosure hit: Unpermitted ADU must be disclosed on listing; buyers expect 15-25% reduction in sale value and title companies may require removal or retroactive permits before closing.
- Utility disconnection: City may order SDG&E or Snohomish PUD to shut off power/water/gas if unit is found unpermitted and deemed unsafe; reconnection requires permit and inspection.
Edmonds ADU permits — the key details
Edmonds Municipal Code Chapter 16.85 governs ADUs, but Washington State law RCW 36.70A.680 (effective January 1, 2023) overrides many local restrictions. The state law requires cities to allow one ADU on any single-family lot without imposing setback, lot-coverage, or lot-size barriers—IF the owner occupies the primary residence. This means a 4,000-square-foot lot in Edmonds that was previously too small under the old local code is now eligible for an ADU, as long as the owner lives in the main house. Edmonds must issue a permit if the application meets state and local standards; the city cannot refuse based on neighborhood character or parking alone. However, the city still enforces building code (IRC), egress (at least one operable window per bedroom, 5.7 square feet minimum; IRC R310.1), foundation (frost depth 12 inches in Puget Sound area per IRC R403.1), and utility rules. Detached ADUs and garage conversions require the same rigor as new houses—plan review, site plan, electrical, plumbing, HVAC specifications, and four to six inspections (foundation, framing, rough trades, final).
Parking is a critical Edmonds-specific rule. State law (RCW 36.70A.680) preempts local parking minimums for ADUs, meaning the city cannot require you to add parking for the ADU if the lot already has code-compliant parking for the main house. However, if your lot does not meet code parking for BOTH units combined, you may be asked to add a space or request a hardship waiver. Edmonds does NOT charge impact fees for ADUs 750 square feet or smaller, which is a major cost advantage. Plan-review fees run $500–$1,500 depending on complexity; building-permit fees are 1.5-2% of the estimated project cost (typically $3,000–$8,000 for a 750-square-foot ADU valued at $200,000–$400,000). If the ADU requires a separate utility meter, Snohomish PUD charges roughly $500–$1,200 for the service drop and meter installation; some ADUs use sub-meters (cheaper, around $300–$500) if the utility company allows it. Owner-occupancy is mandatory for the most-favorable permitting path; if you plan to rent the ADU immediately, you may face additional scrutiny or deed restrictions, and the city may require rental-registration approval from the Planning Department.
Utility and egress requirements are non-negotiable. A detached ADU or garage conversion must have two independent exits if it has more than one bedroom, or one egress if it is a studio or single-bedroom junior ADU (per IRC R310). Bedrooms must have a window that opens to the outside (not a interior hallway) with a minimum clear opening of 5.7 square feet; basement bedrooms need a 'safe and operational' escape route (window well, door, or ramp). Kitchens must have a 3-foot-wide aisle between cabinetry and appliances, and all plumbing must be sized per IRC P2605 for the number of fixtures (a kitchen, one or two bathrooms, laundry hook-up). If the ADU is above a detached garage, the ceiling must be fire-rated (typically 1-hour), and the garage door must remain functional or be permanently closed and inspected. Separate utility accounts (electric, water, sewer) are strongly recommended—not legally mandated, but they simplify future sale, insurance, and rental licensing. If you share utilities via sub-meter, document the split clearly on your site plan and notify the utility company.
Edmonds' lot and setback context: The city sits on glacial till with seasonal high groundwater in some neighborhoods (e.g., near creeks and wetlands). Foundation inspectors often require deeper frost protection (up to 18 inches) if the lot slopes toward retained water or if boring reports show silt/clay. Many Edmonds lots are small (5,000-7,500 square feet) and wooded, which means tree-survey reports and drainage plans are common requirements. The 12-inch frost depth is a baseline, but your engineer or geotechnical report may trigger a deeper requirement. Side and rear setbacks for ADUs are typically 5 feet (consistent with state law preemption), but front setbacks match the primary home's street-facing setback—usually 20-25 feet from the property line. If your lot is a corner lot or sits in a flood zone or landslide-hazard area, additional reviews (usually 2-4 weeks) are required; the city's GIS map shows these overlays clearly. Sloped lots require retaining walls (inspect-heavy, cost $3,000–$8,000) and drainage plans; flat lots are faster to permit.
Timeline and next steps: Edmonds Building Department accepts permit applications online via the Edmonds permit portal or in-person at City Hall (220 4th Avenue, Edmonds, WA 98020). After submission, you have a 2-3 week initial review; expect one round of comments (plan corrections for egress, utility routing, tree-impact mitigation, or setback clarification). Resubmit within 2 weeks and you'll typically get approval for building permit within 4-6 weeks total. Once the permit is issued, you have 12 months to start construction. If the lot is flagged for critical-areas review (wetlands, slope, tree preservation), add 4-8 weeks. Inspections begin once foundation work is visible and continue through final occupancy; plan for one inspection per major phase (foundation, framing, mechanicals, final). Owner-builders may conduct their own work if owner-occupied, but electrical and plumbing typically require licensed sub-contractors (Washington requires journeyman electricians and plumbers, with limited owner-builder exceptions). Budget 6-14 weeks from application to occupancy permit, depending on site complexity and resubmission cycles.
Three Edmonds accessory dwelling unit (adu) scenarios
Washington State ADU Law vs. Edmonds Local Code — What Changed in 2023
Washington State passed strong ADU preemption legislation (RCW 36.70A.680, effective January 1, 2023) that overrides local restrictions in cities like Edmonds. The state law mandates that all cities allow at least one ADU on any single-family residential lot WITHOUT imposing minimum lot size, setback, lot-coverage, or parking minimums—as long as the property owner occupies the primary residence. Before 2023, Edmonds' local code required a minimum lot size (7,500-10,000 sq ft depending on zone) and setbacks (10 feet side, 15 feet rear for detached ADUs). These barriers are now voided; the city MUST issue a permit for an owner-occupied ADU on a 5,000-square-foot lot if all other code requirements (egress, foundation, utilities, fire safety) are met. This is a fundamental shift and makes previously unbuildable lots eligible.
Edmonds Building Department now interprets its code through the lens of state preemption. If an applicant can show owner-occupancy (utility bill, deed, or notarized declaration), setback and lot-size objections cannot block the permit. The city's online permit portal and staff have been updated to flag ADU applications as 'state-preempted' and expedite review. However, the city still enforces fire code (egress, separation, sprinklers if total floor area > 5,500 sq ft on the lot), foundation/structural code (frost depth, soil bearing, seismic design per IBC), and utility code (separate meters, water/sewer capacity). Owner-occupancy must be documented at permit issue; if you later convert to a rental, you may be required to amend the permit or register as a rental with the Planning Department (rental registration is $200–$400 annually in Edmonds).
The state law also waives parking minimums for ADUs in most cases. Edmonds can still require parking if the lot does not meet code for BOTH units combined, but this is rare on developed single-family lots. If the primary home has two parking spaces and code requires two for the main house + one for the ADU (three total), you may need to add a driveway space or request a hardship waiver. The city's policy is to grant waivers liberally for small lots or lots with significant topography. Impact fees (schools, parks, roads) are also waived for ADUs under 750 square feet—a major cost savings compared to a new single-family home, which would trigger $15,000–$25,000 in impact fees.
Edmonds Utility and Drainage Challenges — Glacial Geology and Seasonal Groundwater
Edmonds sits in the Puget Sound Lowland, a glacial landscape with till, silt, and clay soils. The 12-inch frost depth is a baseline, but seasonal high groundwater (October through May) is a real concern, especially on sloped or wooded lots. Many Edmonds building inspectors require a geotechnical boring report if the lot has evidence of seepage (dark soil staining, standing water in winter, proximity to a creek or wetland). A boring report costs $800–$1,500 and can result in a requirement for deeper footings (18-24 inches) or underslab drainage (perforated footing drain, sump pump). If your ADU is a basement or has living space below grade, you MUST have a sump pump and interior or exterior French drain; Edmonds inspectors are vigilant about this because water damage claims spike in late winter.
Snohomish PUD is the primary water and sewer provider in Edmonds. If your lot is within the city but outside PUD service (some Edmonds neighborhoods use alternative systems), you may need a well or septic design—very rare but check your lot card early. For standard PUD service, a new ADU requires a new sewer lateral connection at the main (cost $3,000–$6,000 depending on depth and rock excavation), which must be shown on your site plan and approved by PUD before Edmonds issues the building permit. Water service (meter and service line) is usually tied into the existing main; PUD charges roughly $500–$1,200 for the meter installation and connection. If your lot is heavily treed (common in Edmonds), the site plan must show tree preservation or removal strategy; trees over 6 inches diameter are protected in residential zones and require an arborist report if they are within the building envelope or dripline of the foundation. Tree removal costs $1,500–$5,000 per tree depending on size and hazard.
Drainage is a persistent issue on Edmonds' sloped, wooded lots. If your ADU site requires cut or fill, you must show erosion-control measures (silt fence, erosion-control blanket, swales) on the grading plan. Roof runoff must be managed—either directed to rain gardens, swales, or the city's storm system via a new storm connection. If the lot drains toward a neighbor's property or a protected wetland, the city will require a drainage study and may deny the permit if downstream impacts are significant. Budget 6-8 weeks for drainage-plan review if the lot is sloped or undeveloped. Many Edmonds ADU projects include rain gardens or bioretention swales to reduce stormwater fees and improve approval odds; these add $2,000–$5,000 to the site cost but are worth the investment in a rainy, environmentally conscious city.
220 4th Avenue, Edmonds, WA 98020
Phone: (425) 771-0220 ext. 4600 (verify current extension) | https://permits.ci.edmonds.wa.us (online permit application and status tracking)
Monday–Friday, 8:00 AM – 5:00 PM (closes 4:30 PM on Fridays; closed municipal holidays)
Common questions
Does Washington State law really override Edmonds' lot-size and setback rules for ADUs?
Yes. RCW 36.70A.680 (effective January 1, 2023) mandates that Edmonds allow at least one ADU on any single-family lot without minimum lot size, setback, or lot-coverage barriers—IF the property owner occupies the primary residence. The city cannot deny a permit based on these factors alone. However, the ADU must still meet fire code (egress, fire separation), foundation code (frost depth, soil bearing), and utility code (separate or sub-metered connections). If you plan a rental ADU (non-owner-occupied), the state law does not apply, and Edmonds' local restrictions may still block the project.
Do I need to pay impact fees for an ADU in Edmonds?
No impact fees are charged for ADUs 750 square feet or smaller. If your ADU is larger than 750 sq ft, impact fees (schools, parks, roads) are calculated as a percentage of the additional square footage above 750 sq ft and assessed at the same rate as a single-family addition. Plan-review and building-permit fees (roughly $400–$800 for plan review, $1,500–$3,000 for building permit depending on project complexity) are always required and are separate from impact fees.
Can I build a rental ADU in Edmonds, or do I have to live on-site?
You CAN build a rental ADU, but the permitting process and local restrictions are stricter. State law (RCW 36.70A.680) only preempts local setback/lot-size rules for OWNER-OCCUPIED ADUs. Rental ADUs are subject to Edmonds' full local code, which may require larger lot sizes, greater setbacks, parking, and possible approval from the Planning Department. Additionally, Edmonds requires rental-ADU registration ($200–$400 per year), which involves a license-agreement review and possible deed restriction. For a rental project, budget extra time (4-8 weeks) and higher plan-review costs ($800–$1,500). If owner-occupancy is possible, start with that—it is far easier to permit and convert to rental later.
What is a junior ADU, and how is it different from a full ADU?
A junior ADU is a smaller, owner-occupied accessory dwelling without a separate kitchen. It typically includes a bedroom, full bathroom, and a kitchenette (sink, cooktop, microwave, refrigerator) but NOT a full kitchen with oven and range. Junior ADUs are capped at 500 square feet in Washington State. Because there is no separate kitchen, they do not require a separate sewer lateral connection (the kitchen plumbing ties into the main house), reducing utility costs by roughly $2,000–$3,000. Egress is also simpler: a single operable bedroom window and a door to the main house usually satisfy code. Junior ADUs are faster and cheaper to permit and are ideal for secondary units above garages or in basement spaces. However, they are owner-occupied only and must remain part of the same legal lot as the primary residence.
Do I need a separate meter for the ADU, or can I split the main house meter?
Separate or sub-metered utilities are highly recommended and often required by the city and utility company. For a separate meter, Snohomish PUD will run a second service drop to the property (cost $800–$1,200) and the city will require this shown on your site plan. If the ADU shares a meter with the main house, a sub-meter (cost $300–$500, installed by a licensed electrician) can track usage for billing purposes. However, sub-metering complicates insurance, future rental registration, and potential sale. For owner-occupied ADUs, sharing a meter is acceptable if documented; for rentals, a separate meter is nearly always required by the city and lenders.
How long does it take to get an ADU permit in Edmonds?
Standard owner-occupied ADUs on flat, developed lots with no critical-areas issues: 4-6 weeks from application to permit issuance. If critical-areas review is triggered (slope, wetlands, trees, creek buffer), add 4-8 weeks. If the site requires a retaining wall, geotechnical report, or arborist report, add another 2-4 weeks. Once the permit is issued, you have 12 months to start construction before it expires. Construction time is typically 4-6 months for a detached ADU, 2-3 months for a garage conversion, and 5-8 months for an above-garage unit. Total from application to occupancy: 6-14 weeks for permitting, plus 3-8 months for construction.
Can I pull the ADU permit myself as an owner-builder, or do I need a contractor?
Owner-builders may pull permits and conduct work on owner-occupied ADUs in Washington, with important limits: electrical and plumbing must be performed by licensed journeyman electricians and plumbers (or supervised by one), and gas work requires a licensed technician. You can do the framing, drywall, finish carpentry, and site work yourself. If the ADU is a rental, you MUST use a licensed general contractor to pull and manage the permit. If you are unfamiliar with permitting, hiring a permit expediter (cost $500–$1,500) to manage the application and plan corrections can save time and prevent rejections.
What are the main reasons Edmonds rejects ADU permit applications?
Most common rejections: (1) Inadequate egress (bedroom window too small or blocked, no second exit for two-bedroom units); (2) Utility plan missing or unclear (separate meter not shown, sewer lateral not sized, electrical load unclear); (3) Setback or parking violation for rental ADUs (owner-occupied ADUs are preempted by state law, but rental ADUs still face local restrictions); (4) Site plan missing critical-areas (tree survey, wetland buffer, slope analysis); (5) Foundation design inadequate for soil conditions (no geotechnical report if site is sloped or wet). Submit a complete plan package (site plan, floor plan, elevations, utility diagram, electrical single-line, plumbing isometric, tree survey if any trees on lot) and you will avoid 90% of rejections.
If I build an ADU now as owner-occupied, can I rent it out later without pulling a new permit?
Not without notifying the city. If you initially permit the ADU as owner-occupied (which triggers state-law preemption and faster approval), you may be able to rent it later if you register as a rental with the Planning Department. Registration is administrative (not a full re-permit) and costs $200–$400 per year. However, if the original permit has conditions that restrict non-owner-occupancy, you may need to amend the permit before converting to rental. Check with the Planning Department (planning@ci.edmonds.wa.us) before converting. Some lenders and insurers also require notice of rental conversion, so coordinate early.
What if my lot is in a critical-areas zone (wetlands, slope, stream buffer)? Can I still build an ADU?
Yes, but the permitting process will take longer (add 4-8 weeks for critical-areas review). If the lot has a stream buffer, wetland, or steep slope, Edmonds will require a critical-areas assessment (arborist report, wetland delineation, geotechnical report, hydraulic study, or all of the above). The cost ranges from $1,500–$5,000 depending on complexity. The assessment must prove that the ADU location and grading do not degrade critical areas or violate buffer setbacks. Many Edmonds lots can accommodate an ADU even with critical-areas constraints—the city is growth-friendly—but budget time and money for the study and plan revisions. Early consultation with the city's Planning Department (use the pre-application meeting service, $100–$200) can clarify constraints before you invest in full studies.