Do contractors charge sales tax in Washington?

In Washington a contractor is treated as the RETAILER of what they install in real property. That means the contractor buys the materials tax-free on a resale certificate and charges the customer sales tax on the job. Washington also has county, city or special-district rates on top of the state rate, so the rate depends on where the job site is, not where the contractor is based. Source: RCW 82.04.050(2)(b); WAC 458-20-170 (constructing, repairing or improving real property for a consumer is a retail sale).

WhatWashington
Contractor’s default roleRetailer
What the charge is calledSales Tax
Local rates on topYes — sourced to the job site
Capital improvement exempt to the customerNo

Where this gets more complicated

Washington is the clearest retailer state: the entire contract — labor, materials, overhead and profit — is one taxable retail sale, and the contractor buys materials on resale. Retailing B&O tax also applies to the same receipts and is a separate liability this row does not compute. Public road and government work has its own treatment.

Source

RCW 82.04.050(2)(b); WAC 458-20-170 (constructing, repairing or improving real property for a consumer is a retail sale). — last checked 2026-09-15.

This is a summary of a state’s published guidance, not tax or legal advice. Rates and rules change, local jurisdictions add their own, and the treatment of a specific job depends on the contract and the work. Check the citation and speak to a CPA or a state tax adviser before relying on it.

How Seayora uses this rule

Seayora resolves this rule on every invoice a contractor raises — per line, from the job site’s own address — and prints the rate, the jurisdiction and this citation on the document itself, so the estimate a customer accepts is the invoice they are billed. Where the rule is more nuanced than a single answer, Seayora refuses to guess a total rather than quoting a confident wrong one.

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