What Is the Harbor Maintenance Tax and Who Pays It?

The Harbor Maintenance Tax is a federal fee of 0.125 percent charged on the value of commercial cargo loaded or unloaded at ports maintained with federal funds, and on fares paid by passengers on commercial vessels using those ports.¹ Congress created it in 1986 to fund dredging and upkeep of navigable channels, shifting those costs to the commercial interests that rely on them. If you import goods by water, ship cargo between covered U.S. ports, operate in a foreign trade zone, or run passenger vessels, this fee likely reaches you.

The Rate and How It’s Calculated

The rate is 0.125 percent of cargo value and has not changed since enactment. A shipment worth $100,000 generates a $125 fee; a $2 million container of machinery costs $2,500.¹ The variable in every calculation is how the cargo is valued.

For imported cargo, the fee is based on the appraised value CBP already uses for duty purposes under 19 U.S.C. 1401a — the same transaction value declared on the entry paperwork. For domestic cargo moving between U.S. ports, value comes from standard commercial documentation such as invoices and bills of lading; when none exists, the same customs valuation rules apply. For passenger vessels, the fee applies to the actual fare paid by each passenger, or the prevailing charge for comparable service if no fare is paid.² A vessel operator owes only once per passenger per cruise, even if the ship calls at multiple covered ports.

Who Has to Pay

The statute imposes the fee on “port use,” meaning loading or unloading commercial cargo from a commercial vessel at a qualifying port.³ In practice four groups end up filing and paying:

Importers bringing cargo into the U.S. by vessel.
Domestic shippers moving cargo between covered U.S. ports.
Foreign trade zone operators admitting cargo into a zone.⁴
Commercial passenger vessel operators, since the statutory definition of commercial cargo includes passengers transported for compensation or hire.³

One boundary worth flagging: not every waterfront is a covered port. The statute excludes any channel or harbor where no federal funds have been spent on construction, maintenance, or operation since 1977, and any waterway deauthorized by federal law before 1985.¹ Facilities that have been entirely self-funded for decades are outside the tax.

What’s Exempt

The exemption list is broader than most people expect.

Exports

Cargo leaving the United States for a foreign destination is not subject to the tax. In United States v. United States Shoe Corp. (1998), the Supreme Court held that applying the Harbor Maintenance Tax to exports violated the Constitution’s Export Clause because it was an ad valorem tax rather than a user fee matched to actual port use.⁵ The Court left room for a properly structured user fee on exports, but Congress has not enacted one, so exports have been functionally exempt since 1998.

Government and Humanitarian Cargo

Cargo owned by or shipped on behalf of the U.S. government or any federal agency is fully exempt. Cargo owned or financed by nonprofit organizations and cooperatives is also exempt when CBP certifies it is intended for humanitarian or development assistance overseas.³

Other Statutory and Regulatory Carve-Outs

The regulations exempt several additional categories:²

Cargo on vessels whose fuel is already subject to the Inland Waterways Fuel Tax, preventing double taxation on barge traffic.
Ferries engaged primarily in transporting passengers and their vehicles between U.S. points, or between the U.S. and a contiguous country.
Bunker fuel, ship’s stores, sea stores, and equipment necessary to operate the vessel.
Fish and other aquatic animal life caught at sea and not previously landed on shore.
In-bond cargo entering solely for transportation and direct exportation, subject to special rules for shipments moving to Canada or Mexico.

Small Shipments and De Minimis Thresholds

Imported cargo that qualifies for informal entry procedures is exempt. Domestic shipments valued at $1,000 or less are exempt. And if the total value of all your fee-eligible shipments for a quarter does not exceed $10,000, no quarterly payment is required.⁶ Several anti-stacking rules also apply: moving cargo within the same port doesn’t trigger the fee, unloading and reloading the same cargo from the same vessel counts as a single event, and relay cargo traveling under one bill of lading between vessels at a U.S. port on its way to or from Alaska, Hawaii, or a U.S. possession is taxed only once.³

How to File and Pay

The mechanics split by cargo type.

Importers pay at the time of formal entry. The fee is reported on CBP Form 7501, the Entry Summary, alongside any duties or other charges. If no other duty or fee applies and the harbor maintenance fee exceeds $3, the importer submits payment with the entry forms.²

Domestic shippers, foreign trade zone operators, and passenger vessel operators file quarterly on CBP Form 349, the Harbor Maintenance Fee Quarterly Summary Report. Quarters end March 31, June 30, September 30, and December 31, and payment must reach CBP no later than 31 days after the quarter closes.² The first-quarter payment covering January through March is due by May 1. Form 349 can be submitted electronically through the Automated Clearinghouse system at pay.gov, or mailed with a check to CBP’s Office of Finance in Indianapolis.

Fixing Mistakes and What Happens If You Don’t Pay

If you overpaid, underpaid, or reported the wrong cargo value on a quarterly filing, use CBP Form 350, the Harbor Maintenance Fee Amended Quarterly Summary Report.⁷ Correcting promptly matters, because unresolved discrepancies can trigger penalties once CBP identifies them.

Late or missing payments carry a penalty equal to the liquidated damages CBP assesses for late entry summary filings, and importers are also liable under their basic importation and entry bond.² Relief and mitigation are available under the same procedures that apply to other customs penalties, but compliance is far cheaper than correction.

Keep the paperwork. Records related to harbor maintenance fee filings must be retained for five years from the date of entry or the date of the activity that created the record.⁸ That includes invoices, bills of lading, valuation documentation, and copies of Forms 349 and 7501, regardless of whether the shipment was an import or a domestic move.

1
Office of the Law Revision Counsel. 26 US Code 4461 – Imposition of Tax
2
eCFR. 19 CFR 24.24 – Harbor Maintenance Fee
3
Office of the Law Revision Counsel. 26 US Code 4462 – Definitions and Special Rules
4
U.S. Customs and Border Protection. Harbor Maintenance Fee (HMF)
5
Justia. United States v. United States Shoe Corp.
6
eCFR. 19 CFR 24.24 – Harbor Maintenance Fee
7
U.S. Customs and Border Protection. CBP Form 350 – Harbor Maintenance Fee Amended Quarterly Summary Report
8
eCFR. 19 CFR 163.4 – Record Retention Period