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Washington solar energy system sales tax exemption open

Administered by the Washington State Department of Revenue.

Washington exempts solar energy systems of 1 to 100 kilowatts AC from sales and use tax, on the equipment and, with a qualifying installer, on the installation, for purchases through 31 December 2029. You claim it at the point of sale with the buyer's exemption certificate. Washington has no income tax, so there is no state solar tax credit.

source · verified 2 October 2026 · amounts in US dollars

What it pays

what
100% of the sales and use tax on machinery and equipment used directly in the solar system, and on installation services.
system size
At least 1 kW and no more than 100 kW, AC.
dates
Equipment bought from 1 July 2019 to 31 December 2029; installation begun on or after 1 July 2019 and finished by 31 December 2029. The exemption expires on 1 January 2030.
installer
For the labor to be exempt, the installer must be registered with Labor & Industries, hold a UBI number, industrial insurance, an Employment Security number and an excise tax registration, and have no wage-and-hour violations in the past 24 months.

Larger systems work differently: from 100 to 500 kW, and other renewable systems over 1 kW, the buyer pays the tax and then applies for a partial refund, at 50%, 75% or 100% depending on the project's labor standards.

Who is eligible

who
Buyers of solar energy systems and their installation.
how
Give the seller and the installer a completed Buyers' Retail Sales Tax Exemption Certificate; they keep it for five years.
if you paid tax
Apply to the Department of Revenue for a refund.

Where the application goes

No application to the state before you buy: the certificate goes to your seller and installer.

Where the application goes
If this is youApply here
Department of Revenue: tax incentive programsdor.wa.gov
Larger systems' refundsdor.wa.gov

The thing most pages get wrong

One solar installer's guide tells homeowners to hand over form REV 40 2432A. That form is the refund application for large renewable projects (solar over 500 kW and other systems), with a 50% to 100% refund. A home system uses the Buyers' Retail Sales Tax Exemption Certificate at the point of sale.

No federal credit to add

The federal Residential Clean Energy Credit (25D) ended for systems placed in service after 31 December 2025, so this exemption and your utility's net metering are what is left.