State Nexus Guide
Washington Sales Tax Nexus 2026: B&O Tax & $100K Rule
Washington's economic nexus threshold is $100,000 OR 200 transactions under RCW §82.08.052. But Washington also levies B&O tax separately — what remote sellers must know in 2026.
Washington Sales Tax Nexus — The 2026 Threshold
Washington State imposes economic nexus on remote sellers who have more than $100,000 in cumulative gross receipts from sales into Washington, or more than 200 separate transactions into Washington, during the current or prior calendar year. The statute is RCW §82.08.052, and Washington was one of the earliest states to enact economic nexus legislation — effective October 1, 2018, just months after the Wayfair decision. Washington's dual $100,000/200-transaction threshold uses an 'or' structure: either condition alone creates nexus. A seller with $101,000 in Washington revenue has nexus. A seller with 201 transactions totaling $50,000 also has nexus. Washington has not moved to eliminate the transaction-count prong as of 2026, maintaining the original dual standard. Washington's threshold applies to gross retail sales — including marketplace-facilitated sales. The Washington Department of Revenue (DOR) counts all sales into Washington, including Amazon and other marketplace sales, toward the $100,000/$200-transaction threshold for determining whether the seller has economic nexus for their non-marketplace sales channels. Amazon's collection of Washington sales tax on Amazon.com sales covers the Amazon side; it does not eliminate the seller's obligation for direct sales if economic nexus exists. Washington eliminated its 200-transaction threshold in the legislature... actually, Washington State retains its dual threshold as of 2026. This is a point of confusion because Iowa and Wisconsin eliminated their transaction counts effective January 1, 2026. Washington's DOR has published updated guidance confirming the dual standard remains in effect. What makes Washington unique relative to all other states: Washington levies a separate Business and Occupation (B&O) tax under RCW §82.04.220 on gross receipts from business conducted in Washington — this is not a sales tax but an excise tax on the seller's gross revenue from Washington business activity. Remote sellers who meet Washington's nexus thresholds may owe both Washington sales tax (collected from customers) and Washington B&O tax (paid by the seller on their gross Washington revenue). No other state in this comparison group (California, Texas, Florida, New York) levies a B&O tax alongside sales tax.
What Triggers Nexus in Washington Beyond Sales Volume
Washington's physical nexus and economic nexus rules are defined under RCW §82.08.052 and Washington DOR guidance. Several triggers are specific to Washington's interpretation. FBA inventory in Washington: Amazon operates major fulfillment centers in DuPont, Sumner, Kent, Auburn, and other Washington locations. FBA inventory stored in any Washington Amazon fulfillment center creates physical nexus with no minimum threshold. Physical nexus in Washington means registration and collection obligations for all taxable sales into Washington — regardless of the economic nexus threshold. Washington's marketplace facilitator statute (RCW §82.08.0531) covers Amazon's remittance obligation on marketplace sales, but the seller's physical nexus registration obligation exists independently. B&O tax nexus: Washington's B&O tax has its own nexus standard. Under RCW §82.04.067, a business has substantial nexus in Washington for B&O purposes if it has more than $100,000 in Washington gross receipts. B&O tax rates vary by business classification: retailing is 0.471%, wholesaling is 0.484%, and service businesses pay 1.5% on gross receipts. Remote sellers who meet the $100,000 Washington revenue threshold have both sales tax nexus and B&O tax nexus, and must register and file for both. Public-use computers and server nexus: Washington has historically treated the presence of any owned or leased equipment in Washington — including servers hosted in Washington data centers — as creating physical nexus. Cloud computing providers and SaaS companies that use Washington-based infrastructure (AWS US-West servers in the Quincy, Washington data center complex, for example) may have Washington physical nexus through server location. This is a Washington-specific rule rarely found in other states. Consignees and agents: if an out-of-state seller uses a Washington-based fulfillment service, consignee, or sales agent who regularly sells on the seller's behalf, Washington asserts nexus on the out-of-state seller through the agent's in-state activity.
How to Register in Washington
Washington sales tax and B&O tax registration is administered by the Washington State Department of Revenue. Registration is done online through the Business Licensing Service (BLS) at bls.dor.wa.gov. Both sales tax and B&O tax registration are handled through the same Business License Application. What you need: your EIN (or SSN), legal business name, UBI (Unified Business Identifier) if you have one, primary business address, Washington address if any, expected Washington gross receipts, and banking information for electronic payments. Washington registration through BLS includes a $90 initial business license application fee for out-of-state businesses registering to do business in Washington — one of the few states that charges an upfront registration fee for remote sellers. Processing time: Washington BLS typically processes registrations within 5 to 10 business days. You will receive a Washington State business license and a UBI number, which serves as your tax account identifier for both sales tax and B&O tax. Filing frequency in Washington: sales tax returns are filed monthly for sellers with annual liability over $4,800, quarterly for $1,200 to $4,800, and annually for under $1,200. B&O tax is filed on the same schedule. Washington requires electronic filing for all registered businesses. Returns are filed through the DOR's online portal at dor.wa.gov. One Washington-specific feature: Washington offers a 'Retailing B&O credit' for small businesses, and sellers at the economic nexus threshold should verify whether they qualify for the small business B&O tax credit under RCW §82.04.4451, which can offset some B&O tax liability for sellers with relatively modest Washington gross receipts.
What Washington Audits Look Like
The Washington Department of Revenue has an active audit program and uses multiple data sources for nexus enforcement. Washington DOR receives 1099-K filings from payment processors, uses marketplace facilitator reports to identify third-party sellers with Washington activity, and cross-references public business registration data from other states against its own registration database. Audit triggers specific to Washington: Amazon FBA sellers with inventory in Washington fulfillment centers who are not registered for Washington sales tax and B&O tax; e-commerce businesses with significant Washington shipping volume (Washington DOR uses third-party shipping data to identify unregistered sellers); businesses registered in California or other high-nexus states but not Washington; and companies with AWS or other cloud infrastructure hosted in Washington-based data centers. Washington's statute of limitations for sales tax assessments is four years from the date the tax was due. For B&O tax, the same four-year limitations period applies. For non-filers, Washington takes the position that the four-year limitations period begins on the date the return was due — which means even non-filers have a bounded four-year look-back period, similar to Texas. This is more defined than California's open-ended statute for non-filers. Penalty structure: Washington imposes a 5% penalty for returns filed within one month of the due date, 15% for returns filed from one to two months late, and 25% for returns filed more than two months late. A separate 10% penalty applies for delinquent tax that has not been paid. Interest accrues at Washington's published rate, currently approximately 9 to 10% annually. Washington also imposes an 'evasion penalty' of 50% in cases of willful non-disclosure. Washington has a voluntary disclosure program administered by the DOR that limits look-back to three or four years (depending on circumstances) and typically waives penalties for qualifying applicants. Contact the DOR's Voluntary Disclosure Program unit at dor.wa.gov. Washington's program also covers B&O tax alongside sales tax in a single voluntary disclosure — an efficiency not available in most other states.
Common Washington-Specific Mistakes
Washington's B&O tax, server-nexus rule, and registration fee produce mistakes that are genuinely unique to this state. Forgetting to register for B&O tax: Washington's most common and most expensive Washington-specific mistake. Every business with Washington nexus owes B&O tax on its Washington gross receipts — not just the sales tax collected from customers. Remote sellers who register for Washington sales tax and start collecting from customers but do not file B&O tax returns are only half-compliant. B&O tax returns are filed on the same schedule as sales tax returns through the same DOR portal, but sellers who learned about Washington requirements through sales-tax-focused resources often do not encounter the B&O obligation until an auditor raises it. Server nexus for SaaS companies using AWS: Washington has a long history of asserting nexus based on server presence. SaaS companies and cloud service providers running workloads on AWS US-West-2 (Oregon) are generally not affected — Oregon is in the no-sales-tax camp. But companies using AWS infrastructure in Quincy or other Washington locations, or with servers in Washington-based colocation facilities, may have Washington physical nexus through server presence. This is a Washington-specific rule that does not apply in California, Texas, Florida, or New York. Missing the $90 registration fee: Washington charges an initial $90 business license application fee for out-of-state businesses. Sellers who attempt to register using a system designed for no-fee states and do not complete the payment step end up with an incomplete registration. The BLS portal requires payment before the registration is processed. Not claiming the small business B&O credit: Washington's small business B&O tax credit under RCW §82.04.4451 provides a tax credit that reduces or eliminates B&O liability for businesses below certain gross receipt thresholds. Remote sellers who are at or near the $100,000 Washington nexus threshold may qualify for this credit, meaningfully reducing their B&O tax exposure. Many sellers — particularly those whose tax advisors are unfamiliar with Washington — do not claim it. Assuming the transaction-count threshold has been eliminated: Washington retained its 200-transaction threshold as of 2026. Sellers who read about Iowa and Wisconsin eliminating their transaction counts in January 2026 and assume Washington did the same will have incorrect monitoring parameters for Washington. Always verify current threshold rules with the Washington DOR at dor.wa.gov rather than generalizing from other states' changes.
Key Facts and Figures
These figures are drawn directly from Washington statutes and tax authority guidance.
Washington's economic nexus threshold is $100,000 in gross receipts OR 200 separate transactions into Washington during the current or prior calendar year, under RCW §82.08.052 (effective October 1, 2018, one of the earliest post-Wayfair adoption dates).
Washington is the only state among the five highest-volume nexus states (CA, TX, FL, NY, WA) that levies a Business and Occupation (B&O) tax under RCW §82.04.220 on sellers' gross Washington receipts, in addition to the standard sales tax — remote sellers with Washington nexus owe both.
Washington's B&O tax rate for retail sellers is 0.471% on gross Washington receipts; service businesses pay 1.5% — a separate obligation from sales tax that applies to the seller's own revenue, not the tax collected from customers.
Washington's statute of limitations for sales tax and B&O tax assessments is four years from the date the tax was due, even for non-filers — one of the more defined look-back windows among the five largest nexus-threshold states.
Frequently Asked Questions
I've heard Washington has a separate business tax beyond sales tax. What is the B&O tax and does it apply to me?
Yes. Washington's Business and Occupation (B&O) tax is an excise tax levied on the gross receipts of businesses conducting business in Washington, under RCW §82.04.220. Unlike sales tax, which is collected from customers and passed through to the state, B&O tax is paid by the seller on their own Washington gross revenue — it comes directly out of your margin. If you have Washington nexus (either through the $100,000/$200-transaction economic nexus test or through physical presence), you likely owe both Washington sales tax and B&O tax. The B&O tax rate for retail sellers is 0.471% on Washington gross receipts. Service businesses and SaaS companies pay 1.5%. Both taxes are registered and filed through the same Washington DOR system at dor.wa.gov, but they are tracked separately and you must file a B&O return in addition to your sales tax return.
Does Washington still use a 200-transaction threshold, or has it been eliminated like Iowa and Wisconsin?
Washington still uses the dual $100,000/200-transaction threshold as of 2026. Iowa and Wisconsin eliminated their transaction-count thresholds effective January 1, 2026, but Washington has not made this change. Washington's economic nexus rule under RCW §82.08.052 retains both the $100,000 revenue and 200-transaction conditions, with either alone sufficient to create nexus. If you were monitoring Washington under the impression that the transaction count was removed, update your tracking to continue counting both metrics. The Washington DOR's website at dor.wa.gov publishes current threshold guidance.
My company runs AWS workloads in the Pacific Northwest. Does our server location create Washington nexus?
Potentially. Washington has historically asserted that the presence of owned or leased servers in Washington — including servers in Washington-based data centers — creates physical nexus. AWS's primary Pacific Northwest region is US-West-2, which routes through Oregon, not Washington. However, some AWS infrastructure and colocation data centers are physically located in Quincy and other Washington cities. If your company operates servers in Washington-based facilities, consult the Washington DOR about whether your specific infrastructure arrangement creates Washington physical nexus. This server-nexus theory is less settled than FBA inventory nexus, but Washington has been one of the more aggressive states in asserting it.
How do I register in Washington and what does it cost?
Register through the Washington Business Licensing Service at bls.dor.wa.gov. The registration covers both sales tax and B&O tax in a single application. Unlike most states, Washington charges an initial $90 business license application fee for out-of-state businesses registering to do business in Washington. You will need your EIN, business name, primary address, expected Washington gross receipts, and banking information for electronic payments. Processing takes approximately 5 to 10 business days. You will receive a Washington State business license with a Unified Business Identifier (UBI) number, which is your account identifier for all future filings with the DOR. File returns electronically through dor.wa.gov.
Can I use Washington's voluntary disclosure program to fix past exposure?
Yes. Washington's Department of Revenue administers a voluntary disclosure program that covers both sales tax and B&O tax in a single disclosure — an efficiency advantage compared to states where each tax type requires a separate process. The program typically limits the look-back period to three to four years and waives penalties for qualifying applicants who come forward before the DOR initiates contact. You still owe the underlying tax and interest for the look-back period. Washington's four-year statute of limitations for non-filers means the bounded look-back is already defined by law — but voluntary disclosure waives the penalty layer, which can be substantial for multi-year non-registrants. Contact the DOR's Voluntary Disclosure Program unit at dor.wa.gov to initiate the process before any audit notice or DOR compliance letter arrives.
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