6 min read · Last updated September 30, 2026
- A Davis-Bacon prevailing wage is set through a specific three-step legal test, not a single formula that applies everywhere: a majority rate, then a 30% rule, then a weighted average, in that order.
- The wage is calculated at the county level for a specific type of construction, which is why the rate for the same trade can differ across a county line.
- A 2023 U.S. Department of Labor (DOL) rule, effective October 23, 2023, restored the 30% step after decades in which it had been skipped, specifically to cut back on how often the weighted-average fallback got used.
- A “wage determination” is a published document, not a live calculation. Contractors and workers look up the current rate for their county and craft rather than the survey math itself.
A federal prevailing wage is the output of a three-step legal test run separately for each county and each type of construction. That’s why the published rate for the identical trade can differ across a county line, even though the same federal law applies on both sides of it.
In this article
- The law behind the number: the Davis-Bacon Act
- Why the county line matters
- The 30% rule: eliminated in 1982, restored in 2023
- What this means for reading a wage determination
- Frequently asked questions
Federal law does not set one national wage for construction work paid for with federal money. It sets a specific three-step legal test that produces a different number for nearly every county and every type of work. That’s exactly why an electrician on one side of a county line can be entitled to a different minimum rate than an electrician doing the same job a few miles away.
The law behind the number: the Davis-Bacon Act
The Davis-Bacon Act requires that federally financed or federally assisted construction contracts pay laborers and mechanics no less than the locally prevailing wage and fringe benefit rate for their classification, as determined by the U.S. Department of Labor (DOL). That determination is not a single average wage. Federal regulation (29 C.F.R., the Code of Federal Regulations, § 1.2) defines “prevailing wage” as a strict three-step test, run in order:
- The wage paid to the majority, meaning more than 50%, of workers in that classification on similar projects in the area during the relevant period.
- If no wage clears 50%, the wage paid to the greatest number of workers, as long as that number is at least 30% of those employed in the classification.
- If nothing clears 30% either, the weighted average of all wages paid in that classification, weighted by how many workers earned each rate.
Most people assume “prevailing wage” means something like a market average from the start. It’s actually a majority-rule test first, with the average used only as a last resort when the workforce is too fragmented across pay rates for a majority or a strong plurality to exist.
Why the county line matters
The Department of Labor’s Wage and Hour Division (WHD) publishes the results of this test as a “general wage determination.” The same regulation defines that as a list of wage and fringe benefit rates for various worker classifications, tied to a specific type of construction in a given area, and posted publicly for contractors to use. That area is typically a single county. A separate “project wage determination” can be issued for one specific project instead. That happens most often when the work crosses more than one county, or when no general determination already covers the relevant area and construction type.
Because the underlying survey data, worker classifications, and construction-type categories are collected and calculated county by county, two adjacent counties can land in different steps of the three-step test even for the identical trade. One county’s electricians might cluster tightly enough around one number to clear the 50% majority rule. The neighboring county’s electricians might be spread across enough different rates that the determination falls back to a weighted average instead, producing a materially different published rate for the same job.
The 30% rule: eliminated in 1982, restored in 2023
The 30% step wasn’t always part of the test. It was removed from the regulations in 1982. For four decades after that, any classification without a clean 50% majority went straight to a weighted average, even when a large plurality of workers were paid one clear rate. The Department of Labor found that reliance on weighted averages had more than doubled in that period, which it viewed as inconsistent with the word “prevailing” in the law’s own name. A final rule the department published in the Federal Register on August 23, 2023 restored the 30% rule, effective October 23, 2023. The goal was to reduce how often the weighted-average fallback gets used and bring the standard closer to its original 1930s-era design.
The three-step test, side by side
| Step | Condition | Resulting wage |
|---|---|---|
| 1. Majority rule | More than 50% of surveyed workers in the classification earn the same rate | That single rate becomes the prevailing wage |
| 2. 30% rule (restored 2023) | No majority, but at least 30% of workers earn the same rate | That rate, paid to the largest single group, becomes the prevailing wage |
| 3. Weighted average | No single rate reaches even 30% | A weighted average of all reported rates, weighted by worker count |
What this means for reading a wage determination
A published wage determination is a lookup document, not something a contractor or worker recalculates themselves. In practice, that means the visible number for a given county and trade already reflects whichever of the three steps applied, without the document necessarily stating which step produced it. Two counties can show noticeably different published rates for the same classification. That gap is a legitimate product of local survey data working through the same fixed test, not an error or a sign one county’s contractors are being shortchanged. That’s a different kind of wage floor than how the federal minimum wage is actually set, which applies one flat national rate rather than a county-by-county survey result.
Frequently asked questions
Does Davis-Bacon apply to every construction job? It applies specifically to construction contracts financed or assisted by the federal government above certain dollar thresholds, not to private construction generally. Many states also have their own “little Davis-Bacon” laws that apply similar wage floors to state-funded projects.
What counts as a fringe benefit under a prevailing wage determination? Fringe benefits are contributions toward things like health insurance, retirement plans, vacation, and holiday pay. A contractor can count these toward meeting the total prevailing wage and fringe benefit rate, separately from the base hourly wage.
Why would an agency request a project wage determination instead of using the general one? A project wage determination gets requested when a project spans more than one county, or when no general determination currently covers the relevant area and type of construction. It’s also requested when nearly all the work on the contract will be performed by a worker classification that isn’t listed in the general determination that would otherwise apply.
Can a prevailing wage determination be appealed or corrected? Yes. Contractors, unions, or other interested parties can request a conformance if a needed worker classification is missing from a determination, and formal wage determination disputes go through the Department of Labor’s Administrative Review Board.
Does the type of construction affect the rate, even within the same county? Yes. The Department of Labor issues separate determinations for different construction categories, such as building, highway, heavy, and residential. The same county can have several different published rates for the same trade, depending on which category the project falls under.
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