Seattle port storage charges: four free days

This page is about one American gateway, UN/LOCODE USSEA, and it is the third US port on this site after Los Angeles and Houston. All three publish their own storage tariff rather than leaving the charge to a terminal operator, so all three can be checked before you book. Seattle is the one whose tariff tells you to go and read somebody else’s.

The custodian is neither port

The document that decides what your overstay costs at Seattle is not published by the Port of Seattle. It is The Northwest Seaport Alliance Terminals Tariff No. 300, effective 11 July 2026, issued by the Alliance “as licensee/agent for Ports of Tacoma and Seattle”.

That matters for two practical reasons.

It means one tariff covers two harbours. The North Harbor is Seattle’s terminals; the South Harbor is Tacoma’s. Free time, the start rule, the weekend rule and every rate band are identical at both, so a box diverted from one to the other arrives on the same clock. Nhava Sheva is the counter-example on this site: five container terminals under one port authority publishing free periods of two or three days, in two currencies.

And it means the tariff has gaps by design. Item 001 excludes “any portion of the properties that are leased by, licensed by, or under a service agreement with” the Alliance, “unless the Tariff is incorporated by reference into the lease”. A leased terminal can have its own schedule. The tariff tells you so in its second paragraph.

Four free days, and they are not four days

An import container is allowed four free days. Export containers get ten, seven if they leave by westbound rail, and a container that arrives at the North Intermodal Yard with an unknown destination gets five.

The clock starts at “the first 7 a.m. occurring after container is discharged from a Vessel”. A single daily cut, like Houston’s 6 a.m. and unlike Los Angeles’s 3 a.m., and the practical effect is the same at all three: the hour of discharge is nearly irrelevant and the date is everything.

Then the counting basis, which is where four stops meaning four:

Saturdays, Sundays and Holidays will not be counted.

So a box discharged on a Thursday has its four free days on Friday, Monday, Tuesday and Wednesday, which is six calendar days, and more than that across a public holiday. There is a separate entry on working days or calendar days and how eight published tariffs each count a free day; Seattle joins the working-day half.

And then the calendar changes

The same item, a few lines later:

When wharf demurrage commences at the expiration of Free Time, all days will be counted, including the day the container or chassis is removed from the premises.

Free time excludes the weekend. The charge does not. Los Angeles splits that same contradiction across two items a page apart, which is at least honest about being two rules; Seattle puts both in one paragraph, which makes it easier to read and easier to misread. The day the box gates out is a charged day, so a Monday collection on a box that went into demurrage on the Friday costs three days, not two.

The rate grid, and the one place a chassis costs money

Wharf demurrage is charged per unit per day, in three day bands, and each band is roughly double the one before:

A forty-foot box held fifteen days past its free time therefore costs five days at $50.69, five at $98.85 and five at $197.70, or $1,746.20, not fifteen days at the headline rate. Pricing an overstay off the first band is the commonest way a spreadsheet understates it, which is the arithmetic the demurrage calculator exists to do band by band.

The equipment column is the oddity. At 20 feet, a container mounted on a chassis is charged $47.02, $94.04 and $188.07 instead of the container-only rates, about 75% more. At 40 feet and at 45 feet the container-only, chassis-only and chassis-with-container columns are the same figure. One chassis rule applied across the fleet is wrong at exactly one size.

The sentence that makes Seattle different

Every other terminal tariff this site has read treats the port’s clock and the carrier’s clock as independent. Two charges, two documents, neither referring to the other, and a late clearance pays both. That is the rule the terminal storage charge entry sets out and the one the port layer has published eleven times.

Item 657.000 carries a note that breaks it:

Containerized cargo may be subject to Free Time Rules and Demurrage Charges as carried in ocean carrier’s Tariff. Cargo owners are therefore referred to vessel Tariffs. In the absence of overriding ocean carrier Tariff Rules, Free Time will be granted and Wharf Demurrage or Storage assessed in accordance with Rules, Conditions and Rates named in this Tariff.

The Alliance still bills the ground and the line still bills the box, so this is not the two charges collapsing into one, and there is a separate entry on wharf demurrage and why the word names three different charges on an American import. What the note does is make the port’s published four days a default. Where your carrier’s tariff or service contract says something else about free time on cargo at this terminal, that is what governs.

Which leaves a desk in an awkward position: the number it can look up is not necessarily the number it is counting against, and the number that governs sits in a document the port cannot show it. Carrier free time is a service-contract term that differs between two importers on the same vessel, which is why the free-time table on this page is empty rather than filled with an average.

Who gets the bill, and when that was decided

Two provisions worth reading before a box is ever late.

Storage “will be assessed to the Notify party or their designate, on the Ship Manifest for Import/Export Cargo”, and “Changes to the Notify party must be received before vessel departure”. The party who receives the invoice was fixed by a manifest field filled in before the ship sailed — the same field the notify party entry describes as the one contact detail an importer often cannot correct.

And the alternative to being charged exists but closes early. The Alliance will hold cargo in monthly terminal storage instead, on “a written request … describing the cargo, the type of storage (covered or open), length of time storage will be necessary, and name and address of the Person responsible for storage payment”, accepted “no later than 24 hours prior to the cargo’s arrival”. A desk working from the arrival notice has already missed that deadline. Wharf demurrage, in the tariff’s own definition, is the charge that applies “unless arrangements have been made for storage”. It is what you pay for not having asked in time.

What this costs a desk, and what removes it

None of the above is hard. It is four free days on one calendar, charged days on another, three rate bands that double, one size where the chassis matters, a billing party fixed at sailing, a storage application that closes a day before arrival, and a note saying the carrier’s document may override the whole thing. Per container. At one of eleven gateways on this site, each with its own version of the same seven decisions.

That is the shape of the work rather than its difficulty, and it is why the figures end up in a spreadsheet that holds the number and loses the basis. Demurrage and detention software that counts the tariff that actually governs has to keep three things beside each other per box: the free days, which calendar they are counted on, and which document grants them. Seattle is the port that proves the third one is not optional.