By Josh Howes, Chief Executive Officer, Walker Blue LLC
| IN SHORT Projects that meet prevailing wage and apprenticeship (PWA) requirements can claim five times the base credit: 30% instead of 6% under Section 48. Energy projects under 1 MW of output can get the full rate without meeting PWA. For the rest, the enhanced rate rests on payroll records built during construction. In one district portfolio, a correction of approximately $6,200 protected more than $200,000. |
In our September 2026 review of client conversations, prevailing wage and apprenticeship came up about 25 times, split between investment tax credit projects and Section 179D. Seven of those conversations were about the same problem: a subcontractor underpaid, and the owner wanted to know whether it could be fixed and what it would cost. Owners worried about the cost and the paperwork. Contractors worried about penalties showing up after the job closed.
Most underpayments can be fixed, and the price depends almost entirely on when someone finds them. This article covers the cure, the exceptions that allow the full rate without meeting PWA, and the records that hold up when the credit is claimed. For an overview of the rules themselves, see our prevailing wage and apprenticeship requirements page.
What do PWA requirements cover?
Prevailing wage and apprenticeship (PWA) are labor standards attached to most federal clean energy tax incentives. The statutory rules are in Internal Revenue Code §45(b)(7) and (8), which Sections 45Y, 48, 48E and 179D cross-reference. Treasury finalized the general PWA regulations in June 2024 and the Section 48 and 48E credit rules later.
Prevailing wage
Every laborer and mechanic employed by the taxpayer, a contractor or a subcontractor on construction of the facility must be paid at least the Department of Labor prevailing wage for their classification and location, including bona fide fringe benefits. The rate comes from the wage determination on SAM.gov in effect when the construction contract is executed.
The requirement continues after the project is placed in service. For Section 48 and 48E property, it applies to alteration and repair work for five years after the placed-in-service date. For Section 45 facilities, the period is 10 years. Section 179D has no requirement after placed in service. Owners are least likely to have a process for this window, because the construction team has left by then.
Apprenticeship
Three tests apply together:
- Qualified apprentices perform at least 15% of total labor hours for projects beginning construction after December 31, 2023 (12.5% for 2023 starts).
- Apprentices work within the apprentice-to-journeyworker ratio set by the Department of Labor or the applicable state apprenticeship agency.
- Each contractor and subcontractor that employs four or more different individuals at any time during the work employs at least one qualified apprentice. The count covers everyone who worked on the project, not the crew on site on a given day.
A qualified apprentice is an employee participating in a registered apprenticeship program.
How much does PWA change the credit?
Meeting PWA, or qualifying for an exception, multiplies the base credit by five. A Section 48 geothermal heat pump project beginning construction in 2026 has a 6% base rate and a 30% enhanced rate. On an illustrative $1 million of eligible basis, that is $60,000 against $300,000. Our Section 48 vs. Section 48E guide explains which section a given technology falls under.
Section 179D uses the same structure. For taxable years beginning in 2026, the deduction is $0.59 to $1.19 per square foot at the base amount and $2.97 to $5.94 per square foot with PWA, under Rev. Proc. 2025-32. Section 179D ended for property beginning construction after June 30, 2026. Lookback claims on earlier projects may still be available, depending on placed-in-service timing, ownership and applicable requirements, and on those claims the payroll records decide which amount applies.
The One Big Beautiful Bill Act (H.R. 1, enacted July 4, 2025) moved several credit deadlines. The PWA multiplier did not change.
When can a project claim the full rate without meeting PWA?
Three exceptions apply. The first two allow the full rate without meeting PWA at all. The third covers apprenticeship hours only.
| Exception | Who it covers | What the file needs to show |
|---|---|---|
| Under 1 MW | Facilities and energy projects with a maximum net output under 1 megawatt of electrical (AC) or thermal energy. Section 48E facilities may be aggregated for this test, so several small installations can count as one. Not available for Section 179D. | The output calculation and the equipment ratings behind it. |
| Construction began before January 29, 2023 | Projects that began construction before that date, 60 days after Treasury published Notice 2022-61. | Beginning of construction evidence under the physical work test or the 5% safe harbor. |
| Good faith effort | Apprenticeship hours where a written request went to a registered apprenticeship program covering the project’s area and occupation, generally at least 45 days before the requested start (subsequent requests generally 14 days out), and the program denied it or did not respond within five business days. | Each request, its date, the program it went to and the response. It does not cover prevailing wage. |
For a geothermal heat pump system, the 1 MW test runs on thermal capacity. That figure is an engineering determination, and our engineering team calculates it from equipment ratings and the design before anyone assumes PWA applies, or that it doesn’t.
What happens if a subcontractor underpaid prevailing wage?
The regulations include a cure. For each worker paid below the applicable rate, the taxpayer pays the worker the difference plus interest, calculated at the federal underpayment rate with 6 percentage points in place of 3. The taxpayer also pays the IRS a $5,000 penalty for each affected worker for each year in which the failure occurred. If the failure is due to intentional disregard, the back pay is tripled, and the penalty rises to $10,000 per worker per year.
The per-worker penalty can be waived, but the conditions are narrow. The failure has to have occurred in less than 10% of the worker’s pay periods for the year, or the total underpayment has to be no more than 5% below the required amount. The correction also has to be paid by the last day of the first month after the calendar quarter in which the failure occurred. Meeting that timeline requires someone reading payroll as it arrives.
Timing matters for contractors too. Paying corrections before the taxpayer receives an IRS notice of examination creates a presumption that the failure was not due to intentional disregard, which keeps the back pay and the penalty at the standard amounts.
Apprenticeship shortfalls have their own cure: a penalty of $50 for each labor hour short, or $500 per hour for intentional disregard.
One district portfolio from our September review shows what early detection is worth.
| Portfolio | When the problem was found | Outcome |
|---|---|---|
| K-12 district, project over 1 MW, weekly certified payroll review | During construction, while workers were still on site | Correction of approximately $6,200. Enhanced benefit of more than $200,000 protected. |
The error was found in a weekly payroll review, while the workers were still on site.
What records does a PWA file need?
The taxpayer has to keep records showing compliance for every laborer and mechanic, at every contractor tier. Payroll files alone don’t meet that standard. The file has to connect each payment to a classification, a rate and a wage determination.
| Record | What it shows |
|---|---|
| Wage determination | The SAM.gov determination in effect on the contract execution date, plus any supplemental determinations requested for missing classifications. |
| Worker identification and classification | Name, identifying information, classification, and a description of the work that supports the classification. |
| Hours, rates and fringe benefits | Hours per pay period by classification, hourly rate, and bona fide fringe benefit payments. |
| Payroll records | Payroll records for every contractor and subcontractor, which may include weekly certified payroll such as DOL Form WH-347 or an equivalent report. |
| Apprentice records | Apprentice hours by contractor, program registration, ratio compliance, and participation by each contractor that employed four or more individuals during the work. |
| Apprenticeship requests | Written requests to registered programs, with dates, and the responses, when the project relies on the good faith effort exception. |
| Corrections | The calculation, proof of payment to each worker, and the penalty payment to the IRS. |
| Work after placed in service | Payroll for alteration and repair work during the five-year period for Section 48 and 48E property. |
Who is responsible for PWA compliance?
The taxpayer claiming the credit, regardless of what the construction contract says. A flow-down clause obligates the general contractor to pay prevailing wages. It does not put the records in the owner’s hands, and the IRS asks the taxpayer for them.
The question matters most in a common setup: the contractor holds the subcontracts and the payroll, and the owner holds the credit. Before mobilization, the contract should name who collects payroll records at each tier, how often, and who reads it against the wage determination.
Does PWA still apply when a public owner uses Direct Pay?
Yes, if the underlying credit carries PWA and no exception applies. Under elective pay (Section 6417), a school district, municipality or other applicable entity receives the credit as a payment from the IRS. PWA decides whether that payment is calculated at the base or the enhanced rate, so the same records apply. Our Direct Pay for schools guide covers the filing steps.
Public owners often face a second labor standard. Davis-Bacon applies through the terms of federal funding, and PWA applies through the tax code. A project with grant funding and a tax credit can be subject to both, and the two sets of records overlap without being interchangeable. Our federal grant compliance page covers the Davis-Bacon side.
How Walker Blue supports PWA compliance
Our engineering team reviews payroll records weekly against the wage determination, across every subcontractor tier, from mobilization through closeout. The work covers:
- confirming whether PWA applies, including the 1 MW calculation and the beginning of construction date
- pulling the wage determination for the contract date and checking classifications against the work performed
- tracking apprentice hours, ratios and participation by contractor
- calculating corrections and organizing proof of payment with the project’s tax and legal advisors
- assembling the closeout file and, for Section 48 and 48E property, the five-year alteration and repair record
Build the record while the project is being built
The enhanced rate is protected during construction, not reconstructed at filing. Three things should be set before mobilization: the wage determination tied to the contract date, a payroll reporting schedule for every tier, and an apprenticeship utilization plan, including timely written requests to registered programs when needed. The rest of the file follows from those.
Frequently asked questions
Does PWA apply to every clean energy project?
No. Energy projects with a maximum net output under 1 megawatt, and projects that began construction before January 29, 2023, can qualify for the enhanced rate without meeting PWA. Section 179D has no 1 megawatt exception.
Is the apprenticeship requirement always 15%?
For projects beginning construction after December 31, 2023, qualified apprentices must perform at least 15% of total labor hours. The ratio and participation tests apply at the same time, and the good faith effort exception may cover hours where a timely written request to a registered program covering the area and occupation was denied or went unanswered.
Can a prevailing wage underpayment be fixed after the fact?
Generally yes. The taxpayer pays each affected worker the difference plus interest and pays the IRS $5,000 per worker per year, or triple back pay and $10,000 per worker per year for intentional disregard. Corrections paid by the last day of the first month after the quarter of the failure may avoid the penalty, subject to limits in the regulations, and corrections paid before an IRS exam notice are presumed not to be intentional disregard.
Does the general contractor handle PWA compliance?
Contractors supply most of the payroll, but the taxpayer claiming the credit must keep records that substantiate compliance. A contract clause does not replace those records.
Does PWA apply to Direct Pay projects?
Yes, if the underlying credit carries PWA and no exception applies. When a tax-exempt or government entity claims a credit through elective pay under Section 6417, the PWA requirements for that credit determine whether the payment is calculated at the base or the enhanced rate.
How long does PWA apply after construction ends?
For Section 48 and 48E property, prevailing wage applies to alteration and repair work for five years after the property is placed in service. For Section 45 facilities, the period is 10 years. Section 179D has no requirement after placed in service.
Who reads your payroll records against the wage determination each week? If the answer is nobody, talk to our engineering team before the next pay application.
Sources
- Internal Revenue Code §45(b)(7) and (8), prevailing wage and apprenticeship requirements
- Treas. Reg. §§1.45-7, 1.45-8 and 1.45-12 (T.D. 9998), final prevailing wage, apprenticeship and recordkeeping regulations, June 25, 2024
- Final regulations under Section 48, energy credit, December 2024
- Final regulations under Sections 45Y and 48E, clean electricity production and investment credits, January 15, 2025
- IRS Notice 2022-61, November 30, 2022
- Rev. Proc. 2025-32, §179D amounts for taxable years beginning in 2026
- IRS, Prevailing wage and apprenticeship requirements
- U.S. Department of Labor wage determinations, SAM.gov
This article is provided for general informational purposes and does not constitute tax or legal advice. Qualification for any federal tax incentive depends on project-specific facts, timing, taxpayer eligibility and applicable statutory and regulatory requirements.
Published October 2026. Reviewed by John Kapral, JD, CPA, LLM. Regulatory content is reviewed every six months or when the IRS, Treasury or the Department of Labor issues new guidance. Figures reflect law and guidance as of October 2026. Portfolio figures are project-specific and illustrative; they do not predict the outcome on any other project.
