Davis-Bacon wage determinations, fully explained.

The Davis-Bacon Act of 1931 (40 U.S.C. 3141) requires federal construction contractors above the 2,000 USD threshold to pay laborers and mechanics the locally prevailing wages and fringe benefits for the corresponding classification of work on similar projects in the area. The DOL Wage and Hour Division (WHD) calculates and publishes the prevailing wages as wage determinations (WDs). The contracting officer attaches the applicable WD to the solicitation; primes and subs are obligated to pay according to that WD.

Wage determinations live on sam.gov/wage-determinations. Each WD has a unique number, a modification number, an effective date, and an expiration. The combination of construction type and locality (state plus county or counties) defines which WD applies to a given project. A WD is not optional; it is contractual.

Wage determination (WD)

A WHD-published list of minimum wages and fringe benefits by classification (electrician, ironworker, laborer, etc.) for a given construction type in a given locality. The format is standardized; the content varies by where the project is and what type it is.

WD number

Format like XX20240001. Two-letter state code, four-digit year, four-digit sequence. Plus a modification number suffix (mod 0 is original). The exact WD number plus modification fixes the obligation.

Classification

A specific labor category (Pipefitter, Sheet Metal Worker, Cement Mason, etc.). Each gets a base wage rate and a fringe rate. Total compensation is base plus fringe; payment can be all-cash or split between cash and bona fide fringe benefits.

Conformance

The process for adding a classification not on the WD when the project needs it. SF-1444 to the CO, who routes to WHD. Required when the work cannot be performed by any classification already on the WD.

DBA reaches federal construction contracts above 2,000 USD. The Davis-Bacon and Related Acts (DBRA) is a broader umbrella that extends DBA prevailing-wage protection to many federally-assisted construction projects funded through HUD, FHWA, EPA, USDA, the Build America Buy America provisions, and dozens of other federal funding streams. The contracting agency, the funding statute, and the dollar threshold together determine whether DBA / DBRA applies to a given project.

Direct federal contract

DBA applies when a federal agency is the contracting party and the contract is for construction (alteration, repair, decoration, painting) above 2,000 USD. This is the original DBA scope.

Federally-assisted project

DBRA applies when the federal involvement is funding (grant, loan, loan guarantee, insurance) and the underlying statute incorporates DBA prevailing-wage requirements. Whether DBA prevailing wages apply depends on the funding statute, not the federal agency.

Threshold exceptions

A few statutes raise or lower the 2,000 USD threshold. Some narrow exceptions exist (certain emergency work, certain operations and maintenance). The contracting officer specifies in the solicitation.

Service Contract Act distinction

DBA covers laborers and mechanics on construction. The Service Contract Act (SCA) covers service employees on federal service contracts. The two regimes look similar but use different wage determination sets and different rate structures. See SAM.gov for both, but apply the right one to the contract type.

DBA wage determinations are organized by construction type. The four-type taxonomy is set out in DOL's All Agency Memorandum (AAM) series, principally AAM 130 and its updates. Misclassifying the construction type is one of the most expensive DBA compliance failures because the wage rates differ materially between types.

Building

Construction of sheltered enclosures with walk-in access for housing persons, machinery, equipment, or supplies. Includes commercial buildings, schools, hospitals, office buildings, parking structures. Most non-residential vertical construction.

Residential

Construction, alteration, or repair of single-family houses, apartment buildings up to four stories, and incidental items related to residential structures. The four-story limit is the defining boundary; a five-story residential goes into Building.

Highway

Construction, alteration, or repair of roads, streets, highways, runways, taxiways, alleys, parking areas, and similar projects. Includes bridges that are part of a roadway and incidental drainage and culverts.

Heavy

Everything not Building, Residential, or Highway. Includes power plants, dams, sewage treatment, dredging, tunnels, water supply, electrical transmission. Heavy is the catch-all.

Prevailing wages are local. WHD calculates them based on wage data collected from contractors and unions in the project's county (or area, when WHD groups counties). The county where the project is physically performed governs the WD selection, not the contractor's headquarters and not the contracting agency's location.

Project locality

The county or counties where the work is physically performed. Multi-county projects may require multiple WDs.

Areawide vs project-specific WDs

Most WDs are areawide: published in advance for a given construction type and locality, applicable to any project in that scope. Project-specific WDs are issued when no areawide WD covers the work; rare and slow.

Effective date and modifications

The WD applicable to a project is the WD in effect on the date the contracting officer sets in the solicitation (usually solicitation issuance date plus a 10-day rule for modifications). Mods published after that date generally do not roll into the project unless the contract is amended.

The sam.gov/wage-determinations interface supports two paths: search by WD number (when you have one) or filter by construction type, state, and county (when you do not).

1. Choose the construction type

Building, Residential, Highway, or Heavy. Get this right; the wrong type yields the wrong WD.

2. Select state and county

Enter the state and the county where the project will be performed. Areawide WDs cover the selected county.

3. Apply the effective date filter

Filter for WDs in effect on the date the project applies. The default is current; for an existing solicitation, set the date the contracting officer used.

4. Open the WD

The WD is a downloadable PDF listing each classification, base rate, and fringe rate. Note the WD number, modification number, and date. Confirm the classifications you need are present; if not, plan for conformance.

5. Cross-reference with the solicitation

The contracting officer cites the WD number in the solicitation. Confirm the WD you found matches the cited WD number and modification. Mismatches are a contract drafting defect that the CO can correct via amendment.

For four decades, DOL calculated DBA prevailing wages using a single methodology that critics argued under-counted union rates. In August 2023, DOL published a final rule restoring the three-step methodology that had been in place from the 1930s through 1983, plus several enforcement enhancements. The rule took effect October 23, 2023.

Three-step methodology restored

Step 1: if more than 50% of workers in a classification earn the same rate, that is prevailing. Step 2: if no rate has a majority but 30%+ earn the same rate, that is prevailing. Step 3: weighted average if neither test is met. Pre-1983 method; reverses the 1983 rule that compressed the three steps.

Coverage expansion

Certain truck drivers transporting materials to and from a covered site are now covered. Surveyors performing work on covered projects are now covered. Two narrow expansions that close gaps litigated for years.

Conformance authority strengthened

WHD now has clearer authority to set conformance rates if the contractor and CO cannot agree. Previously the conformance process could stall on dispute; the rule lets WHD impose the rate.

Wage determination update cadence

WDs update more frequently. Old WDs that lagged years behind market conditions should now refresh closer to the actual prevailing market rate.

For the broader DOL Wage and Hour enforcement context (FLSA violations, willful and repeat flags, the V4 API for enforcement records), see DOL Wage and Hour search. DBA enforcement runs through the same WHD apparatus.

• Misclassifying the construction type.A residential job mis-flagged as Building pulls higher commercial wage rates and inflates the contractor's payroll obligation. A Heavy job mis-flagged as Building can do the opposite. The four-type taxonomy is not a casual call.
• Using the wrong WD by date.The WD applicable to a project is the WD in effect on the solicitation date, not the WD in effect today. Pulling today's WD onto an existing project is a contract administration error.
• Ignoring conformance until the work is already underway. If the WD does not have a classification you need, file SF-1444 with the CO before the work starts. Conformance after the fact creates retroactive payroll exposure.
• Treating fringe benefits as optional. The WD specifies a base rate and a fringe rate. Total compensation must equal base plus fringe; if the contractor pays less than the fringe in benefits, the difference must be paid in cash. Skipping fringe is a violation.
• Confusing DBA with the Service Contract Act. Both publish wage determinations on SAM.gov. DBA covers construction; SCA covers service contracts. The wrong WD type is a contract-drafting defect.
• Forgetting that DBRA spreads DBA to federally-assisted work. A project funded through HUD, EPA, or FHWA may carry DBA prevailing-wage requirements even though no federal agency is the direct contracting party. The funding statute determines applicability.

Where DiligenceDesk fits: the orchestrator runs the SAM, FAPIIS, exclusion, DOL enforcement, OSHA, and Section 889 checks that sit alongside DBA wage determination lookup in pre-award diligence. DBA itself is a contract obligation, not a vendor-history signal; DiligenceDesk surfaces the DOL Wage and Hour enforcement record (which includes DBA enforcement actions) so a buyer can spot vendors with a history of DBA violations before award.