Certified Payroll Explained: WH-347, Rules and a Worked Example

By SubcontractorHub Editorial Team·Published October 2026

The first public job is where most HVAC, electrical, roofing, and solar contractors meet certified payroll. The work itself is the same work you do every week. What changes is that your payroll becomes a sworn document, your pay application can be held until it is filed, and a classification error that would be harmless on a private job becomes back wages plus a compliance review. This guide covers when it applies, what the report contains, and a worked payroll week so you can see where the numbers actually come from.

When certified payroll is required

Certified payroll follows prevailing wage requirements. If a job carries a wage determination, it almost always carries a weekly reporting obligation with it. The common triggers:

State rules are where contractors get caught out. California routes public works payroll through the Department of Industrial Relations' electronic certified payroll system, Washington requires intent and affidavit filings through Labor & Industries, and several other states set their own dollar thresholds and classifications. Read the bid documents for the exact requirement and check your state labor department's current rules before you price the job.

What goes on the WH-347

The Department of Labor released a revised WH-347 in January 2025. The form is optional, since you can use your own payroll format, but whatever you submit has to carry the same information. Expect to report:

• Project and contractor details: project name and number, your company, prime or sub status, the payroll number and week ending date, and the wage determination number.
• Each worker: identifying information (the revised form uses a worker entry number in place of full personal details on the public copy), whether they are a journeyworker or registered apprentice, and their work classification.
• Hours by day: straight time and overtime, broken out by classification if a worker did more than one kind of work that week.
• Rates and pay: the hourly rate paid, gross earnings for this project and in total, every deduction, and net pay.
• Statement of Compliance: signed by an owner or officer. It certifies the payroll is correct, that workers were paid in full with no rebates, and how fringe benefits were provided: into approved plans, in cash, or listed as exceptions.

That signature is the part to take seriously. Knowingly submitting a false certified payroll can bring federal criminal and civil false-claims liability, on top of withheld payments and possible debarment. The report is a sworn statement, not a summary of payroll.

How to do certified payroll, step by step

1. Pull the wage determination named in the contract (federal determinations are published on SAM.gov). Use the one incorporated in the contract, not whatever is current today.
2. Classify by the work performed, not by the worker's title. A tech who hangs duct one day and runs low-voltage controls the next may fall under two classifications that week.
3. Track hours by day and by classification. Weekly totals are not enough. Clock-in data from the field is the evidence behind the report.
4. Pay at least base plus fringe. Fringe can be paid into bona fide plans (health, pension, vacation), in cash on the check, or as a mix of both.
5. Calculate overtime on the base rate only. Hours over 40 in a workweek get 1.5× base, and fringe stays at straight time for every hour.
6. Verify apprentices. The reduced apprentice rate only applies to apprentices registered in an approved program and within the allowed ratio. Anyone else is paid the journeyworker rate for the work they did.
7. Complete, sign and submit weekly to the prime or the agency, and keep the records for at least three years after the prime contract is completed.

Worked example: one week for a sheet metal worker on a federal job

An HVAC subcontractor is installing ductwork on a federally funded clinic. The rates below are illustrative. Always use the wage determination in your contract. Suppose the determination lists Sheet Metal Worker: base $38.50/hr, fringe $21.40/hr. The company pays $12.00/hr of fringe into its health and retirement plans and the remaining $9.40/hr in cash on the check. The worker logs 10, 10, 10, 10 and 8 hours Monday to Friday, which is 48 hours in total.

Check it against the determination: 48 hours × $21.40 fringe is $1,027.20, and $576.00 to plans plus $451.20 in cash is exactly $1,027.20. Base wages of $2,002.00 cover 40 hours at $38.50 and 8 hours at $57.75. The payroll complies.

Now the two most common ways this goes wrong:

• Overtime on the loaded rate. If payroll treats $59.90 (base plus fringe) as the hourly rate and pays overtime at 1.5× that, each overtime hour costs $89.85 instead of $79.15 ($57.75 plus $21.40 fringe). It is legal, but it overpays $10.70 per hour, which is $85.60 for this one worker this week. Across a 12-person crew running regular overtime, it adds up to real margin over a summer.
• The wrong classification. If the same worker spent Friday setting rooftop units and the determination lists a different rate for that classification, those 8 hours belong on a separate line at that rate. Paying the whole week at one rate is the most frequent finding in a compliance review, and the fix is back wages for every affected worker.

To model the overtime side of a crew week, the overtime pay calculator handles the 1.5× math, and the apprentice wage calculator shows the stepped rates a registered apprentice moves through.

Common certified payroll mistakes

How certified payroll affects getting paid

On public jobs, certified payroll and the pay application travel together. A general contractor will typically refuse to release a sub's draw until that sub's payrolls are in for the period, because the prime is liable for every tier. Late reports therefore show up as late payment. They sit beside the lien waivers, the retainage held on the job, and the AIA progress billing paperwork as conditions of each payment.

It also belongs in your bid. Prevailing wage rates, fringe, and the office time to produce weekly reports are real job costs. If your estimate uses your normal shop labor rate, the job is underpriced before it starts. Mechanical contractors chasing public work usually price it with commercial contractor software that keeps labor classifications on the job record, and run payroll through construction payroll software that produces the certified report directly rather than retyping it into a PDF each week. If you run an HVAC shop moving into public mechanical work, the HVAC page and HVAC contractor software overview show how estimating, crews, and billing connect on one job.

Certified payroll for solar and electrical contractors

Solar contractors met prevailing wage through the tax code rather than a government contract. Under the Inflation Reduction Act, many clean energy projects could only claim the increased credit amount if laborers and mechanics were paid prevailing wages and a share of hours went to registered apprentices. No WH-347 goes to the DOL in that case, but the project owner needs payroll records detailed enough to prove compliance if the credit is examined, and installers are increasingly asked to supply them. Credit rules changed in 2025, so confirm with the project owner's tax advisor whether the requirements apply to a given project before you price it. See our solar contractor software page for how crews, hours, and job records stay connected.

Frequently Asked Questions

This article is general information for contractors, not legal, tax, or payroll advice. Wage determinations, prevailing wage laws, and reporting systems differ by project and by state and change over time. Confirm the requirements in your contract and with the contracting agency or a qualified advisor.