Washington interconnection applications
63 electric utilities serve Washington (EIA-861, 2025): 3 investor-owned utilitys, 17 municipal utilitys, 24 public power districts, 18 electric cooperatives, 1 federal power agency. Together they serve 3,345,523 residential customers; 66,257 residential customers were on net metering at year-end 2025.
Largest utilities in Washington
Investor-owned utility · 1,104,338 residential customers · Washington
Applications: PowerClerk – PSE Net Metering Interconnection Application Portal
Interconnection process and documents →Municipal utility · 472,309 residential customers · Washington
Applications: Own online portal – City Light online Electric Service Application
Interconnection process and documents →Public power district · 349,905 residential customers · Washington
Applications: Own online portal – Interconnection Application and Net Metering Agreement (Adobe Sign web form)
Interconnection process and documents →Investor-owned utility · 376,350 residential customers · Washington
Applications: PowerClerk – Avista SGI PowerClerk
Interconnection process and documents →Public power district · 223,119 residential customers · Washington
Applications: PDF + email – Net Metering Interconnection Application & Agreement to netmetering@clarkpud.com (or mail to Energy Resources, Customer Generation, PO Box 8900, Vancouver WA 98668)
Interconnection process and documents →Municipal utility · 177,554 residential customers · Washington
Applications: Own online portal – Tacoma Power Solar Application and Interconnection Agreement (DocuSign PowerForm)
Interconnection process and documents →Investor-owned utility · 1,867,246 residential customers · Washington
Applications: PowerClerk – PacifiCorp Net Metering / Customer Generation PowerClerk (all six states)
Interconnection process and documents →Public power district · 50,835 residential customers · Washington
Interconnection process and documents →Public power district · 48,849 residential customers · Washington
Interconnection process and documents →Public power district · 43,160 residential customers · Washington
Interconnection process and documents →Public power district · 42,571 residential customers · Washington
Interconnection process and documents →Electric cooperative · 44,526 residential customers · Washington
Interconnection process and documents →Export compensation among the researched Washington utilities: NEM, Net billing. Rules differ by utility – see each utility page.
Washington interconnection rule
Washington Utilities and Transportation Commission (UTC)
Interconnection ruleWAC 480-108 (480-108-001 to -999) – Electric companies - Interconnection with electric generators · source
Applies toUTC-regulated electrical companies (investor-owned: PSE, Avista, PacifiCorp) for customer generating facilities up to 20 MW; excludes PURPA QFs under WAC 480-107. Not binding on PUDs, munis, coops.
Application formUtility-specific standard application form filed with the UTC and posted on the utility website, internet submission where practical (WAC 480-108-030(1)); must be signed and complete.
TimelinesReceipt notice 5 business days; completeness notice 10 business days; cure 15 business days (Tier 1-2) / 30 (Tier 3); Tier 1 decision 20 BD, Tier 2 30 BD; agreement with approval (Tier 1) or within 5 BD (Tier 2); operation within 1 year of approval (Tier 1-2). Completion requires certificate of completion with permits, electrical inspector approval; utility may witness test (WAC 480-108-050).
FeesNonrefundable application fee caps: $100 (0-25 kW), $500 (26-500 kW), $1,000 (>500 kW-20 MW) (WAC 480-108-030(5)).
InsuranceNo additional insurance necessary for generating facility under 100 kW (WAC 480-108-040(14)); RCW 80.60.040(3) bars utilities from requiring net-metering customers to buy additional liability insurance.
External disconnectTier 1: lockable disconnect not required for certified inverter systems on self-contained meter <=320 A unless L&I requires it (WAC 480-108-020(2)(a)(iv)). Tier 2: visible lockable AC disconnect required but utility may waive for inverter-based systems.
Export compensationNEM – RCW 80.60
Applies to all electric utilities incl. PUDs, munis, coops. Offer required until earlier of 2029-06-30 or 4% of utility's 1996 peak; utilities may then file successor tariff (UTC approval for IOUs).
Consumer-owned utilities (PUDs, munis, coops) must offer net metering under RCW 80.60 (<=100 kW) and may adopt their own additional safety/power-quality/interconnection requirements by governing-body action after notice and comment (RCW 80.60.040(2)), but may not require extra standards, tests or liability insurance for compliant systems (80.60.040(3)).
| Level | Up to | Criteria / review / fee |
|---|---|---|
| Tier 1 | 25 kW | Inverter-based, single-phase, secondary voltage, no system upgrades beyond meter change; aggregate on line section <=15% of annual peak load · Approval/denial within 20 business days after completeness notice · max $100 |
| Tier 2 | 500 kW | Not Tier 1, distribution <=38 kV class, not synchronous; fault current / shared secondary limits · Approval/denial within 30 business days after completeness notice · max $500 |
| Tier 3 | 20000 kW | All other facilities up to 20 MW; studies may be required · Technical review result within 30 business days of completeness · max $1,000 application fee; study deposit max lower of $1,000 or 50% of estimated study cost |
- WAC 480-108: https://app.leg.wa.gov/wac/default.aspx?cite=480-108&full=true (retrieved 2026-11-13)
- RCW 80.60 Net metering: https://app.leg.wa.gov/rcw/default.aspx?cite=80.60&full=true (retrieved 2026-11-13)
All 63 utilities in Washington
- Puget Sound Energy (PSE)1,104,338
- Seattle City Light472,309
- Snohomish County PUD349,905
- Avista Utilities247,159
- Clark Public Utilities223,119
- Tacoma Power (Tacoma Public Utilities)177,554
- Rocky Mountain Power (UT, ID, WY) / Pacific Power (OR, WA, CA)114,998
- PUD No 1 of Benton County50,835
- PUD No 1 of Cowlitz County48,849
- PUD No 2 of Grant County43,160
- PUD No 1 of Chelan County42,571
- Inland Power & Light Company42,351
- PUD No 1 of Grays Harbor County40,116
- Peninsula Light Company35,595
- PUD No 3 of Mason County34,378
- PUD No 1 of Clallam County30,934
- PUD No 1 of Lewis County29,779
- PUD No 1 of Franklin County27,692
- City of Richland26,340
- PUD No 1 of Jefferson County18,750
- PUD No 1 of Okanogan County18,230
- PUD No 1 of Douglas County16,909
- PUD No 2 of Pacific County16,586
- Elmhurst Mutual Power & Light Company15,538
- Orcas Power & Light Cooperative14,034
- Benton Rural Electric Association13,864
- Vera Irrigation District #1512,299
- PUD No 1 of Klickitat County11,977
- Modern Electric Water Company9,504
- City of Port Angeles9,394
- PUD No 1 of Pend Oreille County9,209
- City of Centralia9,118
- City of Ellensburg8,846
- Lakeview Light & Power8,341
- Big Bend Electric Cooperative, Inc.6,365
- Columbia Rural Electric Association, Inc.4,466
- Kootenai Electric Cooperative93
- Northern Lights, Inc.18
- Clearwater Power Company0
- City of Cheney0
- PUD No 1 of Skamania Company0
- PUD No 1 of Mason County0
- Tanner Electric Cooperative0
- Ohop Mutual Light Company, Inc.0
- Parkland Light & Water Company0
- Okanogan County Electric Cooperative, Inc.0
- PUD No 1 of Kittitas County0
- City of Blaine0
- Town of Steilacoom0
- PUD No 1 of Ferry County0
- City of Milton0
- Yakama Power0
- PUD No 1 of Wahkiakum County0
- Nespelem Valley Electric Cooperative, Inc.0
- City of Chewelah0
- Town of Eatonville0
- City of McCleary0
- City of Sumas0
- Town of Ruston0
- City of Coulee Dam0
- Bonneville Power Administration0
- PUD No 1 of Asotin County0
- PUD No 1 of Whatcom County0
Residential customers in Washington per EIA-861 (2025). Customer counts = bundled + delivery-only service (EIA-861 Part A + Part D). Service territory is reported by county; a county can be served by several utilities.
$500 / month
Unlimited interconnection applications. 12-month agreement, signed online. The agreement starts the day you sign; first invoice right away, then monthly.
- Unlimited interconnection applications
- Single-line diagram and site plan for every application
- Pre-submission check against the utility’s requirements
- Homeowner e-signature link for the authorization
- Filing in your utility portal accounts or by the utility’s method
- Utility questions, corrections and resubmissions
- Follow-up through approval, inspection and PTO
- Customer list, exports, API and webhooks
Applications are typically submitted within 2 business days after complete documents. Utility review times are set by each utility.