WA
🌲 Washington State⚡ NEC 2026 from Dec 31, 2026
Washington
Solar Permit Plans.
NEC 2023 Now.
NEC 2026 from Dec 31, 2026.
Washington State enforces NEC 2023 via WAC 296-46B (effective April 1, 2024). On December 31, 2026 — six months away — NEC 2026 takes over. Every Washington solar installation requires an L&I electrical permit. PSE, Seattle City Light, SnoPUD, Avista, and Pacific Power each use distinct interconnection formats. CETA mandates 100% clean electricity by 2045. Every plan set we build is formatted for the correct code and the correct utility.
NEC 2023 — WAC 296-46B
NEC 2026 Transition Dec 31, 2026
L&I Electrical Permit Required
PSE PowerClerk · Seattle City Light · SnoPUD
CETA 100% Clean by 2045
NEC 2023WAC 296-46B — current WA code
Dec 31, 2026NEC 2026 replaces NEC 2023 in WA
L&I PermitRequired before utility PTO
2021 IBCWashington State building code cycle
Washington Solar Permits — 2026
Two Codes, One Transition Date, Five Utilities — Washington Solar in 2026
Permit Design produces Washington State solar permit plan sets for solar installers, EPCs, and roofing companies across all Washington counties. Washington currently enforces NEC 2023 through WAC 296-46B, adopted by L&I effective April 1, 2024. On December 31, 2026 — now six months away — NEC 2026 replaces NEC 2023 statewide. This code transition is confirmed in WAC 296-46B-010 and is the most important Washington electrical code fact for 2026. Projects permitted before December 31, 2026 use NEC 2023. Projects permitted from January 1, 2027 use NEC 2026.
Every Washington grid-tied solar installation requires an electrical permit from L&I or the local AHJ. The L&I permit number must be provided to the utility before the utility will issue Permission to Operate (PTO). Building permits follow the 2021 IBC with Washington State Amendments and the 2021 Washington State Energy Code. Washington's Solar Ready code requires dedicated roof zones and conduit pathways in new home construction.
Washington has five major utility territories — Puget Sound Energy (PSE), Seattle City Light (SCL), Snohomish County PUD (SnoPUD), Avista, and Pacific Power — each with distinct interconnection documentation. PSE uses PowerClerk. HOA restrictions on solar are prohibited under RCW 64.38.055. The Clean Energy Transformation Act (CETA) mandates 100% clean electricity by 2045, making Washington one of the strongest solar policy states in the Pacific Northwest.
Last updated: May 2026 · Reading time: ~8 minutes · NEC 2023 current code, NEC 2026 transition December 31, 2026, and L&I requirements confirmed as of May 2026.
Washington Code Transition
NEC 2023 Now → NEC 2026 from December 31, 2026
Washington's code transition on December 31, 2026 is confirmed in WAC 296-46B-010. Here is exactly what changes and what it means for every Washington project in your pipeline right now.
December 31, 2026 — NEC 2026 Replaces NEC 2023 in Washington State
WAC 296-46B-010 states: "Effective December 31, 2026, the 2026 edition of the National Electrical Code (NFPA 70-2026) is adopted and replaces the 2023 edition." L&I reviews electrical rules every three years — this transition is confirmed and not subject to further legislative delay. Permits applied for before December 31, 2026 will be reviewed under NEC 2023. Permits applied on or after January 1, 2027 are reviewed under NEC 2026. For projects in design or procurement now, the code your permit will be reviewed against depends on your submission date. Permit Design builds to NEC 2023 for all current Washington projects and will transition to NEC 2026 from December 31, 2026.
Current — Until December 30, 2026
NEC 2023 via WAC 296-46B
✅ Adopted April 1, 2024 by L&I
✅ NEC 2023 Article 690 — Solar PV Systems
✅ NEC 2023 §690.12 Rapid Shutdown mandatory
✅ All permits applied before Dec 31, 2026
✅ Every Permit Design WA plan set built to this
Effective December 31, 2026
NEC 2026 via WAC 296-46B-010
⏳ Confirmed in WAC 296-46B-010 — no further delay expected
⏳ L&I CR-102 rulemaking filed for NEC 2026 adoption
⏳ All permits applied January 1, 2027 onward
⏳ Permit Design will build to NEC 2026 from Dec 31, 2026
Building Code
2021 IBC with Washington State Amendments. 2021 Washington State Energy Code. Applied by local AHJ building departments. Solar Ready provisions in new construction require dedicated roof zone + conduit pathway.
Electrical Code
NEC 2023 via WAC 296-46B, enforced by L&I. NEC 2023 Article 690 (Solar PV Systems) and Article 705 (Interconnected Power Production Sources) govern solar. §690.12 Rapid Shutdown mandatory statewide.
AHJ Variation
Some Washington cities and counties operate their own electrical inspection departments rather than using L&I. Seattle, Bellevue, Spokane, and Tacoma run their own programs. Always verify whether the project AHJ uses L&I or local electrical inspectors before applying.
L&I Electrical Permit
Washington L&I Electrical Permit — Required Before Utility PTO
Every Washington State grid-tied solar installation requires an electrical permit from L&I or the local AHJ. The L&I permit number must be provided to the utility before the utility will issue Permission to Operate — making the L&I permit a hard dependency for every Washington solar project.
Standard L&I Permit Process
1. Contractor applies online at L&I Electrical Permit portal (ECLIPS system)
2. L&I issues permit number — keep this reference number
3. Installation proceeds following local building permit
4. L&I inspector performs electrical inspection on completed installation
5. Provide L&I permit number and proof of inspection to utility → PTO issued
AHJs with Local Electrical Programs
Seattle: Seattle DCI (Department of Construction and Inspections) handles electrical — not L&I
Bellevue: Bellevue Development Services — local electrical permit
Spokane: Spokane Building Services — local electrical inspection
Tacoma: City of Tacoma Community and Economic Development
All other WA cities and counties: L&I electrical permit and inspection
PSE PowerClerk Interconnection — 6-Step Process
Step 01 — Apply
Submit interconnection application online via PSE PowerClerk portal. Residential systems under 100 kW use simplified Level 1 or 2 process. Include single-line diagram, system specs, and installer details.
Step 02 — PSE Review
PSE reviews application and issues Approval to Construct. Residential Level 1/2 systems: typically 2–4 weeks. Submit simultaneously with local building permit to run timelines in parallel.
Step 03 — Install
Proceed with installation following local building permit and L&I electrical permit. Keep PSE Approval to Construct on file during installation for inspector reference.
Step 04 — Notice of Completion
After electrical permit is finalized by L&I or local inspector, submit Notice of Completion to PSE via PowerClerk. Attach L&I permit number and proof of electrical inspection.
Step 05 — PSE Tests + Meters
PSE tests the system and installs any new metering required. PSE scheduling typically 1–2 weeks from Notice of Completion to meter installation appointment.
Step 06 — PTO + Net Metering
PSE issues Approval to Energize (PTO) and activates net metering. System begins generating bill credits at the full retail rate for excess generation delivered to the grid.
Washington Utilities
Five Washington Utilities — Each Requiring Distinct Interconnection Documentation
Washington has investor-owned utilities, municipal utilities, and public utility districts — all with distinct interconnection formats. Using the wrong utility's documentation results in rejection at the utility review stage.
Puget Sound Energy (PSE)
Largest WA investor-owned utility
TerritoryEast King Co., Kitsap, Pierce, Thurston, Snohomish (partial)
PortalPowerClerk — online interconnection
Net meteringFull retail rate credits
ISA timeline2–4 weeks residential Level 1/2
CETA mandate100% clean electricity by 2045
Seattle City Light (SCL)
City of Seattle municipal utility
TerritoryCity of Seattle — municipal utility
Electrical permitsSeattle DCI — not L&I
Net meteringFull retail rate credits
ISA timeline4–8 weeks — higher volume jurisdiction
NoteSCL has own interconnection process — separate from PSE format
SnoPUD · Avista · Pacific Power
Snohomish PUD · Eastern WA utilities
SnoPUD territorySnohomish County, Camano Island
Avista territorySpokane and eastern Washington
Pacific PowerYakima area, southeastern WA
Tacoma PowerTacoma — municipal utility
ISA timelines2–4 weeks all PUDs and eastern WA utilities
Western Washington
Seattle · Puget Sound · Olympia · Bellingham
Solar irradianceLower — cloud cover, rain. Still viable — design accordingly.
Key challengeDense tree canopy shading — site assessment critical
UtilitiesPSE, Seattle City Light, SnoPUD, Tacoma Power
Snow loadsModerate — 15–25 psf most western WA counties
Wind loadsCoastal exposure — verify ASCE 7 category by site
Eastern Washington
Spokane · Yakima · Tri-Cities · Wenatchee
Solar irradianceHigher — significantly more sunny days than western WA
Key advantageHigher kWh/kW production — stronger solar ROI per installed watt
UtilitiesAvista (Spokane), Pacific Power (Yakima), various PUDs
Snow loadsHigher — 25–40 psf in Spokane and mountain foothills
Wind loadsColumbia River Gorge corridor — elevated wind exposure
What's Included
Washington Solar Permit Plan Set Contents
Every Washington plan set is NEC 2023 compliant (WAC 296-46B), formatted for L&I electrical permit application, includes 2021 IBC structural requirements, and covers PSE PowerClerk, SCL, SnoPUD, Avista, or Pacific Power interconnection documentation.
Sheet 01
Cover Sheet
NEC 2023 (WAC 296-46B) citation. L&I electrical contractor licence number field and L&I permit number reference. Local AHJ building permit reference. Whether local electrical program (Seattle DCI, Bellevue, Spokane, Tacoma) or L&I applies — annotated on cover. System specs, utility interconnection reference, and CETA compliance notation.
Sheet 02
Site Plan
Scaled site plan with property boundaries, utility meter location, Washington fire code access pathways, and array routing. Western WA: tree shading documentation included. Eastern WA: wind exposure category annotation. PSE, SCL, SnoPUD, Avista, or Pacific Power territory confirmed by address.
Sheet 03
Roof Layout
Panel array layout with roof pitch, attachment documentation, Washington fire setbacks, and rafter sizing. Regional snow loads: Eastern WA (Spokane, Yakima): 25–40 psf. Western WA (Seattle metro, Puget Sound): 15–25 psf. Columbia River Gorge: elevated wind uplift. ASCE 7-22 loads per county applied throughout.
Sheet 04
Single-Line Diagram
NEC 2023 Article 690 and Article 705 compliant electrical schematic. NEC 2023 §690.12 Rapid Shutdown compliance documented — L&I inspectors specifically check RSD documentation. Formatted for PSE PowerClerk Level 1/2 technical review or Seattle City Light interconnection standards.
Sheet 05
Structural Calculations
WA-licensed PE-stamped structural analysis per ASCE 7-22 and 2021 IBC with Washington State Amendments. Dead load, wind load, snow load by county zone. Western WA: moss/debris load consideration. Eastern WA: elevated snow + Columbia Gorge wind. Rafter sizing and penetration documentation for L&I inspector verification.
Sheet 06
Rapid Shutdown
NEC 2023 §690.12 rapid shutdown compliance — mandatory under WAC 296-46B. System boundary, initiating device (RSD compliant inverter or module-level device), array dimensions, and NEC 690.56(C) labelling. L&I and Seattle DCI inspectors both check rapid shutdown documentation as a priority inspection item.
Sheet 07
Utility Interconnection Package
PSE PowerClerk application documentation, SCL interconnection, SnoPUD, Avista, or Pacific Power packages — each formatted to the specific utility's requirements. Submit to utility same day as building permit. L&I permit number field included — must be provided to utility before PTO. Net metering activation documentation included.
Sheet 08
Equipment Datasheets
UL-listed spec sheets for all components — modules, inverters, optimisers, racking. IEEE 1547 and UL 1741 compliance documentation for PSE interconnection review. RCW 64.38.055 HOA compliance notation for applicable projects. Washington Sales Tax Exemption reference for qualifying solar equipment.
Process
How Washington Solar Permit Plan Sets Work
01
Submit Your Washington Project
Send us the county and city — we determine whether L&I or the local electrical program (Seattle, Bellevue, Spokane, Tacoma) applies, identify the correct utility (PSE vs SCL vs SnoPUD vs Avista vs Pacific Power), and confirm western vs eastern WA structural requirements for snow and wind loads.
02
We Build to NEC 2023 + 2021 IBC
NEC 2023 (WAC 296-46B) throughout — NEC 2026 from December 31, 2026. WA-licensed PE-stamped structural calcs with county-specific snow and wind loads. PSE PowerClerk, SCL, SnoPUD, Avista, or Pacific Power interconnection package. L&I contractor fields and permit reference on every cover sheet.
03
Delivered in 24–48 Hours
Your 8-sheet Washington plan set delivered in 24–48 hours. Submit to your local AHJ (building permit), L&I or local electrical department (electrical permit), and utility (interconnection application) all on Day 1 — three parallel tracks from the start. Free revisions until your Washington AHJ approves.
First-Time Washington Clients
Try Us on Your First Washington Project. Free.
New to Permit Design? Send us your first Washington residential solar project and we'll deliver the complete plan set free — NEC 2023, PE-stamped, L&I formatted, and PSE PowerClerk or SCL or SnoPUD interconnection included.
Available for solar installers, EPCs, and roofing companies offering solar installation services. Not available for individual homeowners or end customers. One free residential plan set per company.
Claim Your Free WA Plan Set →
NEC 2023 — WAC 296-46B compliant
L&I electrical permit formatted
PSE · SCL · SnoPUD · Avista · Pacific Power
WA-licensed PE structural stamp
Free revisions until AHJ approval
Washington Solar Market — 2026
Washington Solar by the Numbers
Dec 31, 2026
NEC 2026 Transition Date
WAC 296-46B-010 confirms NEC 2026 replaces NEC 2023 on December 31, 2026. This is a confirmed L&I rulemaking (CR-102), not subject to further delay. Projects permitted before this date use NEC 2023. Projects from January 1, 2027 use NEC 2026. For projects being designed now, the code your permit is reviewed against depends entirely on your submission date to the AHJ.
CETA
100% Clean Electricity by 2045
The Clean Energy Transformation Act requires PSE and Pacific Power to achieve 100% clean electricity by 2045 and eliminate coal by 2025. CETA creates sustained regulatory pressure for utility interconnection expansion, drives structural electricity rate increases that improve solar ROI, and makes Washington one of the most ambitious clean energy policy states in the US.
L&I
Electrical Permit — PTO Dependency
The L&I electrical permit is a hard dependency for every Washington solar project. The utility will not issue Permission to Operate without proof of L&I inspection and the L&I permit number. This creates a three-track parallel process: local building permit, L&I electrical permit, and utility interconnection application — all submitted simultaneously on Day 1 for fastest project timelines.
Solar Ready
Washington State Energy Code
The Washington State Energy Code requires many new homes to include a Solar Ready provision — a dedicated zone on the roof and a conduit pathway from the roof to the electrical panel. Solar Ready homes reduce future installation costs significantly. Washington was among the first states to mandate Solar Ready provisions in residential construction, reflecting the state's strong solar policy environment under CETA.
RCW 64.38.055
HOA Solar Protection
Under RCW 64.38.055, HOA governing documents in Washington cannot prohibit solar panel installations that meet applicable safety standards, are certified by recognised testing laboratories, and comply with the NEC and utility interconnection rules. HOAs may impose reasonable aesthetic restrictions on placement but cannot ban solar outright. This protection applies statewide and has been upheld consistently.
Sales Tax
Solar Equipment Exemption
Washington State exempts qualifying solar energy system components from retail sales tax. The exemption covers solar modules, inverters, and related equipment purchased for use in a solar energy system. Combined with federal incentives and strong net metering from PSE and other utilities, the sales tax exemption makes Washington solar economics favourable despite the state's higher-than-average installation costs driven by western WA labour markets.
Washington AHJ Rejections
Top 3 Reasons Washington Solar Permits Get Rejected
These are the three most common rejection triggers across Washington's counties and cities — all preventable with correctly formatted plan sets.
01
L&I Permit Number Not Provided to Utility — PTO Blocked
The most common Washington solar project delay. The utility — PSE, SCL, SnoPUD, Avista, or Pacific Power — will not issue Permission to Operate without the L&I permit number and proof of electrical inspection. Installers who complete installation without finalising the L&I permit inspection, or who submit the utility interconnection Notice of Completion before finalising the L&I inspection, find their PTO blocked indefinitely. The L&I permit and inspection must be fully closed before the utility will activate net metering.
L&I ECLIPS permit system · WAC 296-46BHow we prevent it: Every Washington plan set includes L&I permit application fields on the cover sheet and a project workflow note confirming the L&I permit must be finalised before the Notice of Completion is submitted to the utility.
02
Wrong Electrical Program — Seattle DCI vs L&I
Seattle, Bellevue, Spokane, and Tacoma run their own electrical inspection programs — not L&I. An installer who submits an L&I electrical permit application for a Seattle project, or formats plan sets for L&I rather than Seattle DCI, will be redirected by L&I to the Seattle DCI and face restart delays. Seattle addresses must go through Seattle DCI (Department of Construction and Inspections), not L&I. This distinction is the most common permitting routing error for out-of-state companies entering the Washington market.
Seattle DCI · L&I ECLIPS · City of Seattle electrical codeHow we prevent it: We verify the electrical inspection authority — L&I or local program — for every Washington project address before building. Seattle, Bellevue, Spokane, and Tacoma projects are clearly annotated for their local electrical program.
03
Rapid Shutdown Not Documented on Single-Line Diagram
NEC 2023 §690.12 rapid shutdown is mandatory under WAC 296-46B for all Washington rooftop solar installations. L&I inspectors and Seattle DCI inspectors specifically check that the rapid shutdown system boundary, initiating device, array dimensions, and 690.56(C) labelling are all shown on the single-line diagram. Plan sets that omit rapid shutdown documentation or reference NEC 2023 without specifically addressing §690.12 receive correction notices requiring resubmission. This is a common error from generic template plan sets not updated for NEC 2023.
NEC 2023 §690.12 · §690.56(C) · WAC 296-46BHow we prevent it: NEC 2023 §690.12 rapid shutdown documentation is included on every Washington single-line diagram and as a standalone sheet where required by the specific AHJ. RSD system boundary, initiating device, and all labelling meet current WAC 296-46B requirements.
See all 8 common plan set rejection reasons → Residential Solar Permit Design →
FAQ
Washington Solar Permit Design — Frequently Asked Questions
Washington currently enforces NEC 2023 via WAC 296-46B, adopted effective April 1, 2024 by L&I. NEC 2026 takes effect December 31, 2026 under WAC 296-46B-010 — a confirmed rulemaking, not subject to further delay. Projects permitted before December 31, 2026 use NEC 2023. Projects from January 1, 2027 use NEC 2026. Building codes follow the 2021 IBC with Washington State Amendments.
Every Washington grid-tied solar installation requires an electrical permit from L&I (or the local electrical program in Seattle, Bellevue, Spokane, or Tacoma). The L&I permit number must be provided to the utility before PTO is issued. Apply via L&I's ECLIPS online portal. The L&I inspection must be completed and the permit fully closed before the utility will activate net metering.
PSE uses the PowerClerk portal: submit application → PSE issues Approval to Construct (2–4 weeks) → install following local permits → submit Notice of Completion with L&I permit number → PSE tests system and installs meters → PSE issues PTO and activates net metering. Submit PSE application same day as local building permit to run timelines in parallel.
The Clean Energy Transformation Act (CETA, 2019) requires Washington's investor-owned utilities — including PSE and Pacific Power — to eliminate coal by 2025 and achieve 100% clean electricity by 2045. CETA creates regulatory pressure for utility solar interconnection expansion, drives structural electricity rate increases that improve solar ROI, and is the foundational driver of Washington's solar market growth.
Yes. NEC 2023 §690.12 rapid shutdown is mandatory under WAC 296-46B for all Washington rooftop solar. The system boundary, initiating device, array dimensions, and NEC 690.56(C) labelling must all be documented in the plan set. L&I inspectors and Seattle DCI inspectors specifically check rapid shutdown documentation during electrical inspection.
PSE serves the Puget Sound region. Seattle City Light serves the City of Seattle. SnoPUD serves Snohomish County and Camano Island. Avista serves Spokane and eastern Washington. Pacific Power (PacifiCorp) serves the Yakima area. Tacoma Power serves Tacoma. Verify the serving utility by project address — not by city or county name. Using the wrong utility's interconnection format restarts the 2–4 week utility review from scratch.
The Washington State Energy Code requires many new homes to be Solar Ready — a dedicated roof zone and conduit pathway from the roof to the electrical panel must be installed during construction. Solar Ready homes reduce future solar installation costs significantly. Washington was among the first states to mandate this provision statewide, reflecting CETA's clean energy priorities.
Under RCW 64.38.055, HOA governing documents cannot prohibit solar panel installations that meet safety standards, are certified by recognised testing laboratories, and comply with NEC and utility interconnection rules. HOAs may impose reasonable aesthetic restrictions but cannot ban solar outright. This protection applies statewide across all Washington communities.
Permit Design delivers Washington solar permit plan sets within 24–48 hours. Every Washington plan set is NEC 2023 compliant (WAC 296-46B), WA-licensed PE-stamped, formatted for L&I or local electrical program, includes PSE PowerClerk or SCL or SnoPUD or Avista or Pacific Power interconnection documentation. NEC 2026 formatted from December 31, 2026. Free revisions until your Washington AHJ approves.
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Neighbouring States
Solar Permit Plan Sets — Pacific Northwest & West Coast
Washington Solar Permits — Built Right.
NEC 2023 Now · NEC 2026 from Dec 31 · L&I Formatted
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