To get paid by a Washington state agency, you submit a Washington State A-19 Invoice Voucher: a single-page form that lists what you provided, what you are owed, and your certification that the claim is accurate. Before the agency can cut a payment, you need a Statewide Vendor (SWV) number from the Office of Financial Management. Once you have that, complete the A-19 with itemized charges, sign the certification, attach your receipts or contract documents, and send the packet to the agency’s accounts payable office. Washington law then gives the agency 30 days to pay, with interest owed if it misses that deadline.
Register for a Statewide Vendor Number First
No Washington state agency can pay you without an SWV number. OFM assigns it, uses it to route funds to your bank account, and generates year-end tax documents against it. You register once, and the number follows you across every state agency.
There are two ways to register. You can complete the Supplier Registration Web Form through DocuSign with a digital signature, or you can download the PDF version from OFM’s website, sign it in ink, and submit it by emailing supplierforms@ofm.wa.gov, faxing (360) 664-3363, or mailing Statewide Registration, PO Box 41450, Olympia, WA 98504-1450.
The form doubles as a substitute W-9. You will supply your legal or business name, mailing address, a contact name and phone number, an email address, and either your Social Security Number or Employer Identification Number, not both. Foreign entities submit an IRS Form W-8 instead. OFM emails your SWV number to the address you provided.
Keep the registration current. If your name, address, tax classification, or banking details change, submit an updated form. Outdated records delay payments or send funds to the wrong account.
How to Fill Out the A-19
Get the A-19 template from the agency you are billing; some post it on their website, and OFM maintains the standard version. The form is one page. What causes rejections is not the length but the level of detail in the description area.
Work through each section:
- Agency information at the top: the billing agency’s name, agency number, and location code. Include any purchase order or contract number that authorized the work. The agency can supply codes you don’t have.
- Vendor or claimant details: your full legal name matching your SWV registration, your remittance address, contact name, email, phone, and your SWV number.
- Invoice voucher ID: a unique tracking number you or the agency assigns. Use a consistent numbering system if you bill regularly.
- Payment details: date of service, a plain-language description of the goods or work, quantity, unit price, and total for each line. Vague entries like “consulting services” with no dates or deliverables get sent back.
- Receiving confirmation: the name of the agency employee who verified delivery or completion, and the date.
- Budget coding: the internal account or budget code the expense should hit. The agency’s project manager or accounts payable staff provide this.
When one voucher covers multiple service dates, put each date on its own line with its charge. Bundling several weeks into a single line invites questions and slows payment.
Sign the Certification Block
Every payment claim against the state carries a signed certification. Under RCW 42.24.080, you certify under penalty of perjury that the charges match the contract or established price, that the claim is just, due, and unpaid, and that the goods or services were actually provided. That language sits on the form itself, and your signature under it carries the weight of a sworn declaration.
If you already submitted a separate invoice to the agency, some agencies waive the vendor signature on the A-19 because the invoice itself serves as authorization. When no separate invoice exists, the certification signature is mandatory. A voucher without it will not be processed.
Attach Your Supporting Documents
An A-19 with no backup will be returned. The agency needs to see that the charges are real and match what you’re claiming. Attach what fits the expense:
- For goods: original receipts, packing slips, or shipping confirmations showing what was delivered and when.
- For services: a copy of the contract or engagement letter, plus deliverables or completion reports.
- For travel: itemized hotel folios, fuel receipts, mileage logs, and meal receipts.
A form returned for missing documents restarts the payment clock. Gather everything before you submit.
Travel and Per Diem Reimbursements
If your A-19 includes travel, Washington sets its own reimbursement caps rather than defaulting to federal GSA rates. As of January 1, 2026, the privately owned vehicle mileage rate is $0.725 per mile. Lodging and meal rates vary by location: the standard rate for most of the state is $110 per night for lodging and $68 per day for meals, while higher-cost cities have their own tiers (Seattle lodging runs $188 to $248 per night depending on season, with $92 in meals; Olympia/Tumwater is $151 to $175 lodging and $80 meals; Spokane, Tacoma, and Vancouver each cluster around $126 to $155 lodging with $86 meals).
These rates come from OFM and update periodically. If your actual costs exceed the cap, you get reimbursed only up to the cap unless your contract specifically approved a higher amount. List each travel expense on its own line with the date, location, and amount.
Where and How to Submit the Form
Send the completed A-19 packet directly to the agency that owes you, not to OFM or the State Treasurer. The agency’s accounts payable department handles intake. Most agencies accept scanned PDFs by email, fax, or regular mail; ask your agency contact which they prefer.
One catch on signatures: several agencies have stopped accepting typed-in electronic signatures on the certification block. They want either a digital signature through a platform like Adobe Sign or DocuSign, or an ink signature on a scanned document. A pasted image of your signature may be rejected.
When You’ll Get Paid
Agencies must mail a warrant or make funds available within 30 days of receiving your properly completed invoice or the goods and services, whichever comes later. A warrant is the state’s version of a check. If you signed up for electronic funds transfer during SWV registration, payment lands faster because it goes straight to your bank.
Miss the 30-day window and the agency owes you interest at 1% per month on the unpaid balance, with a minimum of $1 per month. This applies to written contracts for public works, personal services, goods and services, equipment, and travel. If the agency withholds part of a payment over a performance dispute, it must tell you in writing within eight working days what’s wrong and what you need to do. Once you fix it, the agency has another 30 days to release the withheld amount before interest starts running again.
Grant-funded and federally funded contracts follow a different clock: the 30 days start when the agency receives the grant funds or your compliant payment request, whichever is later. Grant-funded work sometimes pays slower even when your paperwork is clean.
Tax Reporting After Payment
Washington has no state income tax, so the state itself doesn’t require 1099 filings from agencies. Payments you receive as a contractor or vendor are still federal taxable income. Starting January 1, 2026, the federal reporting threshold for Form 1099-NEC rose from $600 to $2,000, so agencies only issue a 1099-NEC if they paid you $2,000 or more in the calendar year. Anything below that is still taxable; the agency simply doesn’t have to report it to the IRS on a 1099.
This is another reason your SWV data matters. The name and taxpayer identification number on file with OFM have to match what the IRS has for you. A mismatch can trigger backup withholding at 24%, meaning the agency sends a quarter of your payment to the IRS instead of to you. If you get a TIN mismatch notice, update your OFM registration right away.
Keep Your Own Records
Save a copy of every A-19 you submit, along with the supporting documents and any correspondence about the payment. The IRS generally wants records supporting income items kept at least three years from the date you file the return reporting that income. Underreport gross income by more than 25% and the retention window stretches to six years. Employment tax records should be kept at least four years.
Agencies retain their own copies as part of central accounting, but counting on someone else’s file when a payment is disputed months later is a poor plan. Your own file with the signed A-19, receipts, and proof of delivery is what protects you if a question comes up.