Services
Container Sales Container Rentals Custom Modifications Mobile Offices
Containers
20-ft Containers 40-ft Containers 40-ft High-Cube One-Trip Used / Cargo-Worthy
Uses
Construction Farm & Agriculture Business & Retail Moving & Home Emergency & Disaster Workshops
More
Service Area Buying Guides Answers Glossary FAQ About Contact Call (276) 237-6144 Get a Quote
Grades and provenance

What does wind and watertight really mean?

Updated August 23, 2026 · Answered by Containers Delivered, Woodlawn VA
The short answer

Wind and watertight means the box keeps weather out and stays dry inside. It does not carry the shipping certification a cargo-worthy label does. For storage on your land that gap rarely matters, since every cargo-worthy container is also wind and watertight. It only matters if you plan to ship the box overseas again, which almost nobody buying for storage does.

The decision hiding behind the two letters WWT

Most people who ask about wind and watertight are not chasing a dictionary definition. They are trying to decide whether a WWT-only listing is a corner worth cutting, or a red flag to walk away from. The honest answer is neither by default: it depends on what you are about to do with the box.

If the container is going to sit on your property and hold tools, feed, furniture or inventory, WWT does the same job as cargo-worthy. If you are buying to resell into the shipping trade, or you want the paperwork that proves it, the certification gap is the whole decision.

What WWT actually promises, and what it skips

Wind and watertight is a weather claim. It means the roof, walls, floor and door seals keep rain and wind-driven moisture out, and the inside of the box stays dry through a season of weather. That is the entire promise.

What it skips is the cargo certification survey that earns a box the cargo-worthy label: the formal sign-off that the structure could still carry freight on an ocean voyage. A WWT box may well pass that survey too. It just has not been put through it, or the paperwork has lapsed.

The one question that settles it

Ask yourself a single question: will this container ever go back to sea? For nearly everyone reading this, the answer is no. A box parked behind a barn, on a jobsite, or next to a garage is never getting craned onto a ship again, so the shipping certification a cargo-worthy grade adds on top of WWT is paperwork you will never use.

The one case where it earns its keep is resale into the freight trade or export use, where a buyer down the line may ask for that certification specifically. Outside that lane, dry and structurally sound is dry and structurally sound, whatever the paperwork says.

Where WWT sits in what we actually sell

Every cargo-worthy container we deliver is also wind and watertight, because the higher grade includes the lower one. We do not separately stock WWT-only units as a discount tier below cargo-worthy; in our yard the two labels describe the same box from two different angles.

What we will not do is sell you an as-is unit and call it WWT. If a box has a soft floor, a rusted-through roof or daylight showing through a seam, it has failed the wind and watertight promise, not just the shipping certification, and it does not leave our lot.

Key takeaways

  • Wind and watertight (WWT) means the box stays dry; it does not carry a shipping certification.
  • Every cargo-worthy container is also WWT, so for storage on your land the distinction rarely matters.
  • The certification only matters if the box may ship freight again, which almost no storage buyer needs.
  • A WWT box can still fail if it develops a soft floor or a leaking seam, so the grade is not permanent.
  • We do not sell as-is units under the WWT name; a dry-inside guarantee comes with every container we deliver.
Close enough for storage purposes. It means weather stays out and the inside stays dry through normal rain, wind and standing water around the box. It is not a lab-grade waterproof rating, just the honest promise that a dry container stays dry.
Sometimes, if a survey confirms the structure still meets the standard. That is a decision for whoever is selling the box at the time, not something that happens automatically.
In practice, no. Every used container we deliver meets both, since a box that is not sound enough to be cargo-worthy would not meet our dry-inside guarantee either.
Still weighing WWT against cargo-worthy

Tell us the job and we will settle it

Call with what the container is for and we will tell you whether the certification actually matters for you.

or (276) 237-6144