Washington RTA Tax (Regional Transit Authority)
The RTA tax is the single biggest variable in a Washington tab bill — and it is decided entirely by your address. Vehicles registered inside the Sound Transit district pay a motor vehicle excise tax on top of the standard fees; those outside it do not, even a street away.
Who pays it
The RTA tax applies to vehicles registered at an address inside the Regional Transit Authority boundary, which covers urbanised parts of King, Pierce and Snohomish counties. The boundary follows a defined district rather than county lines, so an address can be in one of those counties and still be outside the district.
How it is calculated
The tax is a percentage of a depreciated value derived from the vehicle’s manufacturer base price using a statutory schedule — not the market value and not what you paid. Because the depreciation schedule is set in law rather than tracking real resale values, newer vehicles in particular can be assessed higher than owners expect.
Is it deductible?
The RTA portion is value-based, so it generally qualifies as a deductible personal property tax on a federal return, while the flat tab and weight fees do not. Our Washington calculator marks the deductible line.
Checking your address
Because the boundary is precise and the amounts are significant, the Department of Licensing publishes a lookup so you can confirm whether a specific address is inside the district before you buy or move.
Official source
WA DOL — Regional Transit Authority (RTA) tax ↗ — the figures on this page are checked against it, most recently on 2026-08-20. See how we verify fees.
Common questions
What is the RTA tax in Washington?
A motor vehicle excise tax funding Sound Transit, charged on vehicles registered inside the Regional Transit Authority district in the Seattle–Tacoma–Everett area.
Why is my RTA tax so high?
It is calculated from a statutory depreciation schedule applied to the vehicle’s base model price, which often values a car above what it would sell for — particularly in the first few years.
How do I know if I am in the RTA district?
The Department of Licensing provides an address lookup. County alone is not enough, because the boundary runs through King, Pierce and Snohomish counties rather than around them.
Is the RTA tax deductible?
The value-based RTA portion generally is; the flat licence tab and weight fees are not.