How prevailing wages are calculated
Majority rule, the 30% rule, and DOL's wage surveys
Davis-Bacon prevailing wages are calculated from evidence of what workers are actually paid in each county: collective-bargaining agreements where those rates dominate, and the Department of Labor's own wage surveys elsewhere. The method is set out in 29 CFR part 1.
The determination sequence
- Majority rule. If more than half of surveyed workers in a classification are paid the same rate, that rate prevails - this is how union rates become prevailing rates in high-coverage areas.
- The 30% rule. If there's no majority rate, the rate paid to at least 30% of workers prevails. (This step, used from 1935 to 1983, was restored by the 2023 rule update.)
- Weighted average. If no rate clears 30%, DOL uses the weighted average of surveyed rates.
Where the survey data comes from
DOL's Wage and Hour Division runs area wage surveys, collecting project pay data from contractors and interested parties on form WD-10. Survey-based lines carry an SU identifier in the determination; CBA-based lines carry the union local's identifier (how to read them). Between surveys, the 2023 rule lets DOL escalate out-of-date survey rates using the Employment Cost Index.
Why neighboring counties differ
Each determination reflects its own county's evidence - union coverage, survey participation, and construction type all differ, so a trade's rate can change substantially across a county line or between Building and Highway work in the same county.
For the actual current rates, use the lookup guide; for market context on what construction pays by state, see average construction wages.