HUD Form 51001 Partial Payment Estimate: Filing and Submission

HUD Form 51001, the Periodic Estimate for Partial Payment, is the form contractors use to request progress payments on public housing construction and modernization projects. You fill in a running calculation that starts with the contract value and ends with the amount owed for the current period, gather three certifications, and submit the original and one copy to the Public Housing Agency (PHA) overseeing the project, together with the companion schedules that back up your figures.

What You Need Before You Start

Download the form from the HUD forms repository at hud.gov/hudclips/forms. It is a two-sided PDF: the front holds the financial calculation, and the back holds the work-item breakdown and the certification blocks.

Form 51001 does not stand alone. Its line items pull directly from three other HUD forms, so have all of them ready:

HUD-51000, the Schedule of Amounts for Contract Payments, is the master breakdown of your contract price into work categories. The item numbers and descriptions on your periodic estimate have to match this schedule exactly, and no progress payments can be made without an approved schedule on file.¹²
HUD-51002, the Schedule of Change Orders, lists all approved additions and deductions to the original contract. Its totals feed lines 2, 3, 6, and 7 of your estimate.³
HUD-51003 and HUD-51004, the Schedule and Summary of Materials Stored, are required whenever you are claiming payment for materials on site that have not yet been installed. The summary total carries over to line 13 of Form 51001.⁴

Filling In the Header

The top of the form collects identifying data: the PHA name, project location, project number, contractor name, and contract number. These should match your original contract documents exactly.

Two header fields cause the most trouble. The periodic estimate number is a sequential count. Your first request is Estimate No. 1, the next is No. 2, and so on. The period covered goes in the “From” and “To” fields in month/day/year format.¹ The “From” date on the current estimate cannot overlap with the “To” date on the previous one. Overlapping periods are a common reason for rejection because the PHA cannot tell which period’s work is being billed.

Completing the Financial Calculation

The front of the form walks through a sequential calculation. Each line feeds the next, so an error on an early line cascades through everything below it.

Line 1 is the original contract amount, the base contract price before any modifications. Lines 2 and 3 are the change order additions and deductions, pulled from Columns 3 and 5 of HUD-51002. Line 4 is the current adjusted contract amount, which is line 1 plus or minus the net of lines 2 and 3.

The back of the form is where you record what you have earned. In Column 3, for each work category from your HUD-51000 schedule, enter the accumulated dollar value of work completed through the closing date of the estimate, then total the column at the bottom.

Line 13 covers materials stored. Enter the value from HUD-51004, but only up to 90 percent of the estimated value of stored materials will be credited.⁴ If you have $100,000 in materials on site, only $90,000 can be carried to line 13.

Line 9 is retainage. Enter both the percentage and the dollar amount. For public housing contracts under HUD’s General Conditions (Form HUD-5370), the PHA retains ten percent of progress payments until completion and acceptance of all work.⁵

After subtracting retainage from total earnings, subtract all previous payments already received. The result is the net amount due for the current period. If the contract includes back-off costs or liquidated damages, enter those as well so the final figure reflects every deduction the PHA will apply.¹

Documenting Stored Materials

Claiming stored materials requires more than the HUD-51003 and 51004 forms. You need verifiable proof of ownership and value, which normally means original invoices or bills of sale.

Off-site storage is stricter. The contractor must obtain a risk-of-loss insurance policy covering the materials during storage, in transit, and until installation at the project site. The policy must name the mortgagor, the mortgagee, and the HUD Commissioner as their interests may appear, and proof of insurance must reach HUD before any payment for off-site components will be approved.⁶

Certifications and Signatures

Three signatures are required before the form can be processed. Payment requests frequently stall here.

The contractor’s certification comes first. An authorized representative of the contracting firm signs a statement certifying that all items and amounts on the form are correct, that all work was performed and materials supplied in accordance with the contract, and that payments to subcontractors and suppliers have been made from previous payments received.¹ Under the False Claims Act, knowingly submitting a false claim to the federal government can trigger civil penalties plus three times the amount of damages the government sustains.⁷

The two remaining signatures come from the PHA. Both an Authorized Project Representative and the Contracting Officer must certify that they have checked and verified the estimate, inspected the work and materials (personally or through authorized assistants), and confirmed that everything complies with the contract terms, drawings, specifications, and applicable accessibility requirements.¹ The PHA’s architect or inspector will normally visit the site before these signatures are applied.

Submitting the Package

Submit the original and one copy of HUD Form 51001 to the Public Housing Agency.¹ Attach the current HUD-51002 to each copy of the estimate,³ and if you are claiming stored materials, attach HUD-51003 and 51004 as well.⁴

Under HUD’s General Conditions, the contractor submits periodic estimates on forms provided by the PHA, and the estimates must be approved by the Contracting Officer with the concurrence of the Architect before payment is released.⁵ If the inspector finds discrepancies between claimed progress and actual work on site, the form comes back for revisions and the review clock restarts.

When Payment Is Due

The PHA makes progress payments approximately every 30 days as work proceeds, based on estimates approved by the Contracting Officer.⁵ Under federal prompt payment rules, progress payments on construction contracts are due within 14 days after the designated billing office receives a proper payment request, though the solicitation may specify a longer inspection period.⁸

When the agency misses that deadline, the Prompt Payment Act requires it to pay interest. For the first half of 2026, the rate is 4.125 percent, and Treasury resets it every six months.⁹ If your request is defective (missing information, math errors, incomplete certifications), the agency must return it within seven days with a written explanation of the defect, and the 14-day clock does not start again until you resubmit a corrected request.¹⁰

Retainage Release

The ten percent held back throughout the project is released after completion and final acceptance of all work. The due date for release is either the date named in your contract or, if no date is named, 30 days after the Contracting Officer approves the release.⁸ The same Prompt Payment interest rate applies if the agency misses that deadline.

Paying Subcontractors

Once you receive a progress payment, you have seven days to pay your subcontractors for their share of the completed work.⁸ Your certification on the form already states that timely payments have been made and will continue. Missing the seven-day window creates both a contract violation and a potential false-claims issue.

Mistakes That Get the Form Sent Back

Most rejected estimates trace back to a short list of recurring problems. Catch these before submission and you save weeks:

Math errors in the running total. The form is sequential; a mistake on line 4 flows through every line below it.
Item numbers that do not match HUD-51000. Adding or renumbering work categories without an approved change order will trigger a return.
Missing companion forms. No current HUD-51002, or no HUD-51003 and 51004 when stored materials are claimed, leaves the PHA no way to verify your figures.
Overlapping date ranges between the current and previous estimate.
Incomplete signature blocks. All three (contractor representative, authorized project representative, contracting officer) need name, title, and date. A missing signature means the form is not a valid payment request.
Claiming more than 90 percent of the value of stored materials on line 13.

A project ledger that tracks each estimate number, period covered, amount requested, and date paid helps you spot patterns in review times and catch discrepancies before the PHA does. A signed copy of the approved estimate is your formal confirmation that funds have been cleared for release.

1
U.S. Department of Housing and Urban Development. HUD Form 51001 – Periodic Estimate for Partial Payment
2
U.S. Department of Housing and Urban Development. HUD Form 51000 – Schedule of Amounts for Contract Payments
3
U.S. Department of Housing and Urban Development. HUD Form 51002 – Schedule of Change Orders
4
U.S. Department of Housing and Urban Development. HUD Form 51004 – Summary of Materials Stored
5
U.S. Department of Housing and Urban Development. General Conditions for Construction Contracts – Public Housing Programs
6
U.S. Department of Housing and Urban Development. Amendment to the Construction Contract for Payment for Components Stored Offsite
7
Office of the Law Revision Counsel. 31 USC 3729 – False Claims
8
Acquisition.GOV. Prompt Payment for Construction Contracts
9
Bureau of the Fiscal Service. Prompt Payment
10
Office of the Law Revision Counsel. 31 USC 3903 – Regulations