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Last updated: May 2026
Avg. sun hours/day
3.6 hrs
Avg. electricity rate
$0.11/kWh
Active incentives
3
Full state and local sales tax exemption (~10%) on solar PV equipment ≤ 100 kW capacity and battery storage installed for residential or commercial use. Saves approximately $1,500 on a $15,000 system.
Under RCW 82.08.962 and 82.12.962, machinery and equipment used to generate or store renewable electric energy is exempt from Washington state and local sales/use tax for systems ≤ 100 kW. Solar PV modules, inverters, mounting, and battery storage all qualify. Exemption is applied at point of sale by the installer using a buyer's exemption certificate. Installation labour is similarly exempt when bundled with the equipment. The exemption was extended multiple times and is in effect through at least 2029 per current statute.
100% exemption from local property tax assessment for the value added by qualifying solar PV systems. Available for systems ≤ 30 kW residential.
Under RCW 84.36.045, residential solar PV systems ≤ 30 kW are exempt from property tax assessment of the value added. Exemption is filed with the local County Assessor. Continues for the life of the system. Larger residential and commercial systems subject to standard assessment with potential local-jurisdiction abatement programmes.
1:1 net metering at retail rate for systems ≤ 100 kW. Annual reset of unused credits at the utility's avoided cost rate.
Washington requires investor-owned utilities (Puget Sound Energy, Avista, Pacific Power) and many municipal utilities (Seattle City Light, Tacoma Power, Snohomish PUD) to offer 1:1 retail-rate net metering for solar systems up to 100 kW. Surplus generation rolls forward through the year; April 30 anniversary settles unused credits at the utility's avoided cost rate. Some municipal utilities offer indefinite roll-forward. Washington's modest solar irradiance (~3.6 PSH) is offset by relatively low electricity rates ($0.11/kWh average), making payback longer than sun-belt states but still feasible (12–15 years post-ITC expiration).
Historical state production incentive paying $0.15–$0.54/kWh for solar generation. Closed to new applicants in 2020 after capacity exhaustion.
Washington operated a State Production Incentive program from 2005 to 2020 that paid solar generators per-kWh production payments at rates that varied based on system characteristics (Made-in-Washington bonus could push rates above $0.50/kWh). The program closed to new applicants on June 30, 2020 with capacity fully subscribed. Existing participants continue to receive payments through their original contract terms, typically 8 years per system. New residential solar in Washington has no equivalent direct production incentive.
Expired for systems placed in service after December 31, 2025.
Federal Section 25D expired 2026-01-01. Washington's modest solar irradiance and lower retail rates mean post-ITC payback periods of 12–15 years are typical for residential installations in 2026. The state sales tax exemption substantially helps but doesn't fully offset the federal credit loss. See /guides/solar-after-itc-expired.
Our calculator uses Washington's actual sun hours (3.6 hrs/day) and electricity rates.
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