How to Fill Out and Submit NAVFAC Form 4330: WAWF and Retainage

NAVFAC Form 4330, the Contractor’s Monthly Estimate for Voucher and Contractor’s Certification, is the progress payment request you file each month on a Naval Facilities Engineering Systems Command construction contract. You complete it using your government-approved Schedule of Prices, attach the subcontractor substantiation the FAR requires, sign the certification, and submit the package electronically through Wide Area Workflow inside the Procurement Integrated Enterprise Environment. Getting paid on schedule depends on the form matching your contract exactly and the certification being both signed and truthful.

What to Gather Before You Start

Pull your contract documents first. You need the contract number, the current contract amount including every executed modification, and the exact period this voucher covers. The form identifies the project by activity, location, and contract title, and those fields have to match your award documents. A mismatch gets the invoice returned before anyone looks at the dollar amounts.

The document that drives the numbers is your Schedule of Prices, typically prepared on NAVFAC Form 4330/4. It breaks the contract into line items with quantities, material costs, labor costs, and totals, and it functions as the financial blueprint for every progress payment. If the Resident Officer in Charge of Construction (ROICC) has not approved your Schedule of Prices, your payment requests will not be processed.

Federal Acquisition Regulation 52.232-5(b) requires five categories of backup with every progress payment request:

An itemized breakdown of the amounts requested, tied to specific contract line items.
The amount included for work performed by each subcontractor during this billing period.
The total value of each subcontract under the prime contract.
Amounts already paid to each subcontractor.
Any additional data the Contracting Officer requests.

The subcontractor detail is where first-time filers most often fall short. The government wants a clear trail showing money is flowing down to your subs, and that trail connects directly to the certification you sign later in the process.¹

Completing the Financial Fields

The form works from gross to net. You start with the total value of work completed from project inception through the current billing period, calculated as a percentage of each line item on the Schedule of Prices. Government field inspectors verify those percentages against daily logs and their own observations, so the numbers need to hold up on inspection.

The calculation moves through these figures in order:

Gross amount due to date, meaning the cumulative value of all work in place plus any approved modifications.
Less retainage, which is the percentage the government withholds.
Less previous invoiced amounts already paid on prior vouchers.
Net amount this voucher, which is what the government owes for the current period.

Materials on Site and Off Site

The Contracting Officer can authorize payment for materials delivered to the site and for preparatory work, even before those materials are installed. Off-site materials can also qualify, but only when the contract specifically authorizes off-site payments and you provide satisfactory proof of title and intent to use the materials on the project.¹

In practice, off-site claims call for bills of sale, warehouse receipts, and insurance certificates covering the stored materials. If your contract has no clause authorizing off-site payments, you will not be reimbursed regardless of how well the claim is documented. Confirm the contract language before you commit to an off-site storage arrangement you intend to bill.

Retainage

Retainage is the portion of each progress payment held back as security for completion. Under federal rules, it cannot exceed 10 percent of the approved estimated amount. The Contracting Officer decides whether to withhold retainage and how much, based on past performance and the likelihood of continued satisfactory progress.²

Retainage is not automatic. If the Contracting Officer finds satisfactory progress during the billing period, payment can be authorized in full. When retainage is applied, the amount can be reduced as the project approaches completion. Once all contract requirements are complete, any retained amounts must be paid promptly. If your performance record justifies a reduction, raise it directly with the Contracting Officer rather than waiting.

The Contractor Certification

Every progress payment request must include a signed certification, or the government will not process the payment. The certification language comes from FAR 52.232-5(c) and covers four statements:

The amounts requested are only for work performed in accordance with contract specifications and terms.
Payments owed to subcontractors and suppliers from previous progress payments have been made, and timely payments will be made from the current payment.
The request does not include amounts the prime contractor intends to withhold from a subcontractor or supplier under the subcontract terms.
The certification does not constitute final acceptance of a subcontractor’s performance. This fourth statement is optional and may be deleted.

The second point is the government’s lever on downstream payment. You are certifying under penalty of law that money from prior payments has already reached your subs and that the current payment will too.¹

The certification carries real legal exposure. Under the False Claims Act, knowingly submitting a false claim to the government triggers civil penalties between $14,308 and $28,619 per violation, plus treble damages, meaning three times whatever the government lost because of the false claim.³

Paying Subcontractors Within Seven Days

Federal construction contracts require the prime contractor to include a prompt payment clause in every subcontract. Under FAR 52.232-27, once you receive a progress payment from the government, you have seven days to pay each subcontractor for their share of satisfactory work covered by that payment. The obligation reaches material suppliers, specialty trades, and any other firm performing under the contract.⁴

The seven-day clock starts when you receive the government’s payment, not when you process it internally. If you hold subcontractor payments and then certify on your next 4330 that all prior subcontractor payments were made, you have signed a false certification with the consequences described above.

Submitting Through WAWF

NAVFAC construction invoices go in electronically through the Wide Area Workflow system, which operates inside the Procurement Integrated Enterprise Environment (PIEE) at piee.eb.mil. WAWF is the Defense Department’s standard platform for invoice submission, government inspection, and acceptance.⁵

If you have not used the system, register for a PIEE account and configure your machine according to the portal’s guide. The Defense Finance and Accounting Service identifies NAVFAC submissions as “Navy Construction Payment Invoice” document types within iRAPT, the invoicing module inside PIEE. You will need your contract number and the specific contract line item numbers to create the invoice.⁶

Some contracts still call for initial submission to the ROICC for manual review before electronic processing. Check your contract’s payment instructions; the designated billing office and any special submission requirements are spelled out there. Keep the contract open while entering data, because WAWF validates certain fields against the contract record and mismatches will stop the submission.

After You Submit

Once the billing office receives the invoice, two clocks start: the government’s review for completeness and the payment deadline under the Prompt Payment Act.

Defective Invoice Returns

If your invoice fails the requirements for a proper invoice, the designated billing office must return it within seven days of receipt, with the specific reasons it is deficient. Common problems are missing subcontractor payment data, math errors between the Schedule of Prices and the voucher, and an unsigned certification. A returned invoice resets the payment clock entirely; the government’s obligation to pay does not begin until it receives a corrected, proper invoice.⁴

Payment Timing and Late Interest

The Prompt Payment Act, codified at 31 U.S.C. Chapter 39, governs how quickly the government must pay after receiving a proper invoice. For construction contracts, the standard payment period is 14 days from receipt, though specific contract terms can extend it to 30 days.⁷

When the government misses that window, it owes interest. The rate is set by the Secretary of the Treasury and published in the Federal Register every six months. For January 1 through June 30, 2026, the Prompt Payment Act interest rate is 4.125 percent.⁸

You do not need to request the interest. The government is required to include it automatically when a payment is late. Track your submission status in PIEE to see where the invoice sits in the approval chain, and if a late payment arrives without interest, raise it with the Contracting Officer’s office.

Mistakes That Delay Payment

Most delays come from avoidable errors on the contractor’s side. The certification is the single biggest stumbling block. A missing signature or missing subcontractor payment detail guarantees a return, and there is no workaround.

Percentage overstatements are the next common problem. When claimed completion percentages do not match what the government inspector sees in the field, the invoice is held while the discrepancy is resolved. Conservative estimates that survive inspection move faster than aggressive ones that trigger a dispute.

Math errors between the Schedule of Prices and the voucher happen often on contracts with many line items and multiple modifications. Confirm that your current contract amount reflects every approved change order. If a modification was recently executed but has not yet been incorporated into your schedule, flag it clearly rather than leaving the billing office to reconcile the difference.

Watch the subcontractor documentation. The five-part substantiation under FAR 52.232-5(b) calls for each subcontractor’s total contract value, work performed this period, and cumulative payments to date, listed separately. Lumping subcontractor costs into a single line item will get the invoice returned.¹

1
Acquisition.GOV. 48 CFR 52.232-5 – Payments Under Fixed-Price Construction Contracts
2
Acquisition.GOV. 48 CFR 32.103 – Progress Payments Under Construction Contracts
3
eCFR. 28 CFR Part 85 – Civil Monetary Penalties Inflation Adjustment
4
Acquisition.GOV. 48 CFR 52.232-27 – Prompt Payment for Construction Contracts
5
Procurement Integrated Enterprise Environment. WAWF Functional Information
6
Defense Finance and Accounting Service. Contractor and Vendor Payment Information Booklet
7
Office of the Law Revision Counsel. 31 USC Chapter 39 – Prompt Payment
8
Bureau of the Fiscal Service. Prompt Payment