Washington / Snohomish County

Solar Permit in Snohomish County, Washington

By Mario Bailey Last checked 2026-07-06 · 2 official sources

Verified against official sources From an official source

It depends

Quick answer

In unincorporated Snohomish County a ground-mounted residential solar photovoltaic system never requires a building or mechanical permit. A roof-mounted residential system on a detached single-family house is exempt from a building or mechanical permit if the total dead load of the panels and mounting hardware is 3.5 pounds per square foot or less (slightly higher for frameless panels on steep-sloped roofs), the panels are mounted no more than 18 inches above the roof, and an electrical permit for the system has already been issued. Systems that do not meet these criteria, and all commercial systems, require a mechanical permit. An electrical permit through the Washington State Department of Labor and Industries is required for every residential solar installation regardless of whether a building/mechanical permit is needed.

Typical threshold: ground-mounted residential solar PV systems never need a building or mechanical permit; roof-mounted residential PV on a detached single-family house is exempt from a building/mechanical permit only if total dead load is 3.5 lbs per sq ft or less (up to 4.5 lbs per sq ft for frameless panels on a 3:12 or steeper slope, or 5 lbs per sq ft for frameless panels on a 5:12 or steeper slope), panels are mounted 18 inches or less above the roof surface, and an electrical permit has already been issued; a separate electrical permit through WA L&I is always required regardless.

Who is pulling this permit?

Apply yourself

Apply on the Snohomish County permit portal

Hire it out

Before you sign, ask the contractor:

  • Who pulls the permit, you or me, and is the permit fee included in the bid?
  • Which inspections will this job need, and who meets the inspector on site?
  • Is your contractor license active in this locality, and under which business name?
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When a permit is usually needed

Before installing a roof-mounted residential solar PV system that exceeds the dead-load or height limits, or any commercial solar PV system, in unincorporated Snohomish County; an L&I electrical permit is required for every installation

What solar permit costs in Snohomish County

Ground-mounted and qualifying roof-mounted residential solar PV need no county building or mechanical permit, though a state L&I electrical permit is still required; non-qualifying systems price from the PDS valuation table starting at a $45 permit fee plus $29.25 plan check at the lowest valuation bracket, plus a $150 base fee per application, the $6.50 state surcharge and a 3% technology surcharge, per PDS Bulletin 18 effective 3/13/2026.

Official fee schedule

How Snohomish County compares in Washington

Across the Washington jurisdictions we have verified, the same threshold runs from 3.5 to 4, so a project that is exempt here may still need a permit one county over.

JurisdictionPermit needed?Threshold
BellevueIt dependselectrical permit required for all solar systems; building permit not required for rooftop single-family systems with dead load under 3.5 lbs per sq ft and panels no more than 18 inches above roof surface
Clark CountyPermit requiredSeparate SOL permits are required for ground mounted units or panels mounted on existing buildings; in new construction the solar panels are included in the NHC or ADS permit.
King CountyIt dependsroof-mounted solar PV panels weighing less than 4 pounds per square foot on residences do not require a building permit; heavier installations require a permit
Pierce CountyPermit requiredNot specified
SeattlePermit requiredNot specified
Snohomish Countythis pageIt dependsground-mounted residential solar PV systems never need a building or mechanical permit; roof-mounted residential PV on a detached single-family house is exempt from a building/mechanical permit only if total dead load is 3.5 lbs per sq ft or less (up to 4.5 lbs per sq ft for frameless panels on a 3:12 or steeper slope, or 5 lbs per sq ft for frameless panels on a 5:12 or steeper slope), panels are mounted 18 inches or less above the roof surface, and an electrical permit has already been issued; a separate electrical permit through WA L&I is always required regardless
TacomaPermit requiredNot specified

How to apply in Snohomish County

A rooftop solar PV permit application is a combined structural and electrical plan set: a site plan and roof framing details proving the array's mounting can carry its added loads, plus a one line electrical diagram covering listed modules and inverters, disconnects, and the rapid shutdown design. Utility interconnection is a separate approval that runs in parallel with the permit.

What most solar permit applications include:

  • Both a building permit and a separate electrical permit are required, since the array must be designed and installed to the residential code's solar provisions and to the National Electrical Code (IRC R324.3).
  • The plan set identifies listed equipment: PV modules listed to UL 1703 (or both UL 61730-1 and UL 61730-2), and inverters listed to UL 1741, with grid-tied inverters listed for utility interaction (IRC R324.3.1).
  • Structural drawings show that the roof framing is designed to structurally support the array and withstand the gravity loads it adds (IRC R324.4.1).
  • The site plan lays out roof access pathways at least 36 inches wide, plus a ridge setback sized to how much of the roof the array covers, so firefighters retain pathways and ventilation access (IRC R324.6.1, IRC R324.6.2).
  • The one line electrical diagram shows the rapid shutdown method and the location of its single initiation device, since one control point must bring all system conductors down to safe levels (NEC 690.12, NEC 690.56(C)).
  • Interconnecting the array to the utility grid at a defined point of connection is a separate application process from the local building or electrical permit and must be approved before the system can operate (NEC 705.12).
  • Some permitting offices route applications through SolarAPP+, an automated review platform that checks the plan set against code requirements and issues eligible permits instantly (DOE SolarAPP+).

General submittal guidance from IRC 2021 R324 (Solar Energy Systems) and NEC 2020 Article 690 (Solar Photovoltaic Systems) and Article 705 (Interconnected Power Production Sources). Source. Snohomish County Planning and Development Services sets the exact checklist for Snohomish County.

Where to apply in Snohomish County:

Snohomish County Planning and Development Services

Inspections and closing out your permit

Inspectors verify the installed array against the approved plans, and some agencies run a rough check of roof attachments and penetrations while they are still exposed before the wiring and roofing close them in. The final inspection confirms rapid shutdown, disconnects, grounding, and required labels are installed correctly, and the system cannot be energized until the utility separately approves interconnection.

  1. Where an agency runs a rough or pre-inspection, it checks the array's roof penetrations while they are still exposed, confirming they are flashed and sealed (IRC R324.4.3).
  2. The inspector confirms whether rapid shutdown is required, how it is accomplished, and that it is properly identified (NEC 690.12, NEC 690.56(C)).
  3. PV disconnecting means must be permanently marked and installed where they are readily accessible, which the inspector confirms in the field (NEC 690.13).
  4. Bonding and grounding of the array, including every exposed non current carrying metal part and the grounding electrode system, is checked before sign off (NEC 690.43, NEC 690.47).
  5. At the service equipment, the inspector looks for the required rapid shutdown placard, a labeled diagram showing the initiation device's location in the specified colors and letter sizes (NEC 690.56(C)).
  6. Utility interconnection is inspected and approved separately from the local building department's sign off, and the system cannot be energized until both approvals are in hand (NEC 705.12).

Schedule each inspection in advance and pass the final before you use the work or close the permit. Request inspections through the Snohomish County permit portal or by phone at 425-388-3311.

Inspection sequence from NEC 2020 Article 690 (690.12 rapid shutdown, 690.13 disconnects, 690.43/690.47 grounding, 690.56 labeling) and IRC 2021 R324.4.3 (roof penetrations). Source. An open permit left un-inspected can surface later in a title search or home sale.

Frequently asked questions

Do you need a solar permit in Snohomish County?
In unincorporated Snohomish County a ground-mounted residential solar photovoltaic system never requires a building or mechanical permit. A roof-mounted residential system on a detached single-family house is exempt from a building or mechanical permit if the total dead load of the panels and mounting hardware is 3.5 pounds per square foot or less (slightly higher for frameless panels on steep-sloped roofs), the panels are mounted no more than 18 inches above the roof, and an electrical permit for the system has already been issued. Systems that do not meet these criteria, and all commercial systems, require a mechanical permit. An electrical permit through the Washington State Department of Labor and Industries is required for every residential solar installation regardless of whether a building/mechanical permit is needed. Ground-mounted residential solar PV systems never need a building or mechanical permit; roof-mounted residential PV on a detached single-family house is exempt from a building/mechanical permit only if total dead load is 3.5 lbs per sq ft or less (up to 4.5 lbs per sq ft for frameless panels on a 3:12 or steeper slope, or 5 lbs per sq ft for frameless panels on a 5:12 or steeper slope), panels are mounted 18 inches or less above the roof surface, and an electrical permit has already been issued; a separate electrical permit through WA L&I is always required regardless. Always confirm with the office before starting.
How much does a solar permit cost in Snohomish County?
Ground-mounted and qualifying roof-mounted residential solar PV need no county building or mechanical permit, though a state L&I electrical permit is still required; non-qualifying systems price from the PDS valuation table starting at a $45 permit fee plus $29.25 plan check at the lowest valuation bracket, plus a $150 base fee per application, the $6.50 state surcharge and a 3% technology surcharge, per PDS Bulletin 18 effective 3/13/2026. See the official fee schedule for current amounts.
Where do you apply for a solar permit in Snohomish County?
You can apply through the Snohomish County permit portal or contact the Snohomish County Planning and Development Services directly. The links are listed on this page.

From the Library

What else needs a permit in Snohomish County

Every other permit type we have verified for this jurisdiction, with the rule that applies here.

ProjectPermit needed?ThresholdTypical fee
Deck PermitIt dependsuncovered decks, deck steps, and uncovered porches for residential buildings exempt if 30 inches or less above adjacent grade at any point, not over a basement or story below, and not part of a required accessible route; covered or taller decks require a permitBase application fee $150 per application plus 3% technology surcharge and $6.50 Washin...
Electrical PermitPermit requiredNot specifiedNo county fee;
Fence PermitIt dependsfences 8 feet or less in height exempt, provided they have no masonry or concrete elements above 6 feet (wire strands atop an 8-foot fence are excluded from the height measurement); taller fences, or fences with masonry/concrete above 6 feet, require a permitBase application fee $150 per application plus 3% technology surcharge and $6.50 Washin...
HVAC PermitPermit requiredNot specifiedFiled as a Mech/Plbg residential trade permit priced from the PDS valuation table start...
Patio PermitIt dependsopen at-grade patios are treated as exempt sidewalks and driveways under SCC 30.50.103(1)(e) with no size limit; freestanding patio covers (roofed, not attached to another structure) are exempt only if 200 sq ft or less inside the UGA or 400 sq ft or less outside the UGA; larger or attached patio covers require a permitPriced from the PDS valuation table starting at a $45 permit fee plus $29.25 plan check...
Plumbing PermitPermit requiredNot specifiedFiled as a Mech/Plbg residential trade permit priced from the PDS valuation table start...
Pool PermitIt dependsprefabricated swimming pools regulated under the IRC (one- and two-family dwellings) exempt if less than 24 inches deep, with no gallon-volume cap; in-ground pools or pools 24 inches deep or more require a building permitPriced from the PDS valuation table starting at a $45 permit fee plus $29.25 plan check...
Roof Replacement PermitIt dependsre-roof overlay or tear-off-and-replace of a residential roof exempt if limited to 2 total layers of roofing material, uses the same type of roofing material as the existing roof, and the roof sheathing is not removed or replaced; adding a layer beyond 2, changing material type, or replacing sheathing requires a permitA like-for-like reroof limited to 2 layers with no sheathing removal needs no permit;
Shed PermitIt dependsone-story detached accessory structure not used for human habitation (tool/storage shed, playhouse) exempt if floor area is 200 sq ft or less and sidewalls 9 ft or less inside the Urban Growth Area (UGA), or 400 sq ft or less and sidewalls 11 ft or less outside the UGA; larger structures require a building permitBase application fee $150 per application plus 3% technology surcharge and $6.50 Washin...

Solar Permit in other Washington localities

Official sources

Verified by a person against the sources above on 2026-07-06, not confirmed with Snohomish County Planning and Development Services. Rules change; confirm before you build. How we verify.

Last checked: 2026-07-06Report an error on this page

Compare Solar Permit requirements across Washington localities