Certified Payroll in Washington State

If you're a contractor or subcontractor on a Washington public works job, you're working under one of the more distinctive prevailing wage systems in the country. Washington doesn't just ask for weekly certified payroll — it wraps the whole project in a paperwork lifecycle called the Intent and Affidavit process, administered by the state Department of Labor & Industries (L&I). Miss a step and payment on the contract can stall. This guide walks through who is covered, how the lifecycle works, and where the federal Form WH-347 fits in.

Who's covered: RCW 39.12

Washington's prevailing wage law lives in chapter 39.12 RCW. It applies to public works — construction, reconstruction, maintenance, and repair performed for the state, counties, cities, school districts, and other public agencies — and to building service maintenance under public contracts. The Department of Labor & Industries publishes the prevailing rates of wage by county and by trade, and it administers compliance. Coverage questions can get fact-specific (off-site fabrication, maintenance contracts, mixed funding), so when in doubt, verify with L&I or your awarding agency before the first worker clocks in. L&I's public works hub is the official starting point: lni.wa.gov public works projects.

The Intent and Affidavit lifecycle

This is the part that surprises contractors coming from other states. Beyond paying the right rates, every contractor and subcontractor on a covered project files two documents with L&I through its online Prevailing Wage Intent & Affidavit (PWIA)system, and filing fees apply (verify the current fee with L&I):

Stage	Filing	What it does
Before work / payment	Statement of Intent to Pay Prevailing Wages	Declares the classifications and prevailing rates you intend to pay on the project. Awarding agencies generally can't release payment until an approved Intent is on file.
During the work	Certified payroll records	Pay the published rates and keep accurate payroll records; certified payroll is filed through L&I's online system (see below).
At completion	Affidavit of Wages Paid	Certifies, after the work is done, that workers were actually paid the prevailing rates. Final payment and release of retainage typically wait on an approved Affidavit.

Both filings are per contractor, per project — a general contractor with five subs means six Intents and six Affidavits. Because payment is tied to these approvals, filing late is one of the most expensive mistakes on a Washington public job even when every worker was paid correctly.

Certified payroll records and the L&I portal

Washington also requires certified payroll itself. Following 2019 legislation, phased in around 2020, contractors and subcontractors on public works must file certified payroll records through L&I's online system— the same portal that handles Intents and Affidavits. The records cover the familiar certified payroll content: each worker's name, classification, hours by day, rate of pay, usual benefits, gross, deductions, and net, certified as true and correct. The exact cadence and which projects are in scope have evolved since the requirement was introduced, so confirm current L&I rules for your projectrather than assuming last year's practice still applies. Whatever the portal asks for, the underlying discipline is the same: accurate weekly payroll records, classified correctly, at or above the published rate.

Overtime in Washington: watch the daily rules and 4-10s

Washington has its own overtime rules layered on top of prevailing wage, and public works scheduling in the state commonly involves four 10-hour days ("4-10s")under a valid work-schedule agreement. Whether hours beyond 8 in a day trigger a premium on your project depends on the applicable state rules and any scheduling agreement in place — verify with L&I and your contract before assuming a 10-hour day is all straight time.

On federally funded work, the federal rule is simpler and unforgiving in a different way: overtime is owed on hours over 40 in the workweek, at 1.5× the base hourly rate plus fringe at straight time — the fringe is never multiplied by 1.5. Getting that multiplier wrong is the single most common math error on certified payroll, in Washington or anywhere else.

Federal overlap: when the WH-347 also applies

A Washington project that receives federal funds — highway money, FTA or FAA grants, federally assisted housing — is typically covered by the Davis-Bacon Act as well asRCW 39.12. In that case both systems apply at once: you file your Intent, Affidavit, and L&I certified payroll on the state side, and you submit a weekly federal certified payroll — usually on Form WH-347or an equivalent — with its signed Statement of Compliance to the contracting agency. Where the state and federal rates differ for a classification, the general rule is that the higher applicable rate wins. Your contract documents should say which wage determinations apply; if they don't, ask before the first payroll, not after.

Looking up Washington prevailing wage rates

L&I publishes the prevailing rates by county and trade, with each classification showing an hourly rate that includes a usual-benefits component. Rates are updated periodically and the rate that governs your job is generally tied to specific dates connected to your contract — so pull the rate for your county, your trade, and your project's applicable datefrom L&I's lookup, and keep a copy with your job records. Don't reuse a rate from a previous job in the same county; it may have changed.

Common mistakes on Washington public works

Filing the Intent late— or not at all — and then wondering why the awarding agency won't release payment.
Forgetting the Affidavit at closeout, which holds up final payment and retainage long after the crew has moved on.
Wrong classification — paying a laborer rate for work the scope book puts under a higher-paid trade.
Using a stale rateinstead of the rate applicable to the project's effective date.
Assuming state filings cover a federal job.On mixed funding, the WH-347 weekly submission is a separate obligation from the L&I filings.
Overtime math — multiplying the full package by 1.5 on federal work, or ignoring daily-hour rules on the state side.

How Certiwage helps

Certiwage takes your crew's hours and rates and produces a clean, weekly certified payroll report with correct gross, overtime, and net — applying the proper federal overtime formula and checking your fringe packageagainst the required rate so a shortfall is caught before you certify, not after an auditor finds it. It stores only the last four digits of each SSN. You handle the filings themselves — the Intent, the Affidavit, and uploads per L&I's system or your contract — and Certiwage makes sure the payroll you're certifying is right. Certiwage is a document-preparation tool, not legal advice, and is not affiliated with L&I or the U.S. Department of Labor. Plans are on our pricing page, or compare another state's system in our California DIR eCPR guide.

The quickest way to sanity-check your numbers is to run one week through the free WH-347 builder — no signup, and the fringe and overtime math is checked for you.