The condition grade determines how long a container lasts. It also determines whether you can convert the unit, whether valuable equipment can be stored inside, and whether the visible cosmetics matter for your application.
The grade sections below run from the most worn grade to the cleanest.
Economy (No Certification)
The lowest grade we sell. A used container that has been retired from active shipping but has not been certified to a specific standard. Expect:
Surface rust on most external panels.
Paint chipping, faded original branding, evidence of multiple repaints.
Dents and dings on side walls and roof. None should be deep enough to compromise structural integrity.
Floor wear: original plywood with industrial residue, possible burn marks, possible patches.
Door hardware functional but stiff.
Best for: Rough storage on a working farm or jobsite, where appearance is not a factor and the unit will be locked and forgotten. Not recommended for storage of valuable, rust-sensitive, or moisture-sensitive contents without ventilation upgrades.
Photos to expect: Visible rust streaks, chipped paint, repaired patches. Doors open and close but show wear. The unit is unmistakably second-hand.
Wind and Water Tight (WWT)
WWT means the container has been inspected and certified to keep wind and water out. Specifically:
Door seals checked and confirmed weatherproof.
Roof inspected for holes, dents, and rust through-spots.
Floor inspected and confirmed structurally sound. May show wear but no rot, no holes, no soft spots.
Walls inspected and confirmed solid. Surface rust and cosmetic dings are acceptable.
Lock boxes and door hardware functional.
WWT is not the same as cargo worthy. WWT means the container keeps wind and rain out. Cargo worthy adds the structural certification needed for international ocean shipping.
Best for: General storage, contractor jobsite tools, farm equipment, household goods during a renovation, on-site materials during construction.
Photos to expect: External panels show some surface rust and cosmetic wear, but doors close cleanly, seals look intact, and the interior is dry. The unit looks used but functional.
Cargo Worthy (CW)
Cargo worthy is a structural certification, not just a cosmetic grade. A CW container has been inspected to the IICL (Institute of International Container Lessors) standard and certified safe for international ocean shipping. That means:
All structural members (corner castings, side and end frames, undercarriage) inspected and confirmed sound.
Walls, roof, and floor confirmed weatherproof and load-rated.
Door hardware tested.
The unit can be loaded onto a ship and sent across an ocean without further inspection.
For storage, CW works much like WWT; the difference is the certification for ocean shipping. Pricing sits between WWT and one-trip.
Best for: Buyers who plan to ship the container internationally at any point, buyers who want a documented certification for resale or insurance purposes, buyers who want better cosmetics than WWT without paying for one-trip.
Photos to expect: Cleaner overall appearance than WWT, with visible age but a more uniform exterior. Documentation accompanies the unit.
One-Trip (Sometimes Sold as Like-New)
A one-trip container has made a single ocean voyage, typically loaded from a manufacturing facility in Asia to a North American port. After unloading, the unit goes into the resale market essentially brand new. Specifically:
Original factory paint, with minor scuffs from the single shipping journey.
Floor in excellent condition, no industrial wear.
Doors and seals tight, lock boxes pristine.
Interior clean and dry, no residue.
Minor cosmetic marks consistent with one ocean trip and one truck transfer.
One-trip carries the longest warranty on the scale. For any conversion project, any food-adjacent storage, any high-visibility placement, or any clean-finish workshop or office build, one-trip is the practical starting point.
Best for: Conversion projects (offices, workshops, tap rooms, tiny homes), food-adjacent or sensitive storage, customer-facing placement, and anyone who wants the cleanest grade.
Photos to expect: Factory paint, sharp graphics, clean interior. Looks like a new container with light handling marks.
Warranty by Grade
Container One's warranty depends on the grade:
Grade
Warranty
One-Trip
10 year structural and 10 year no-leak
Cargo Worthy
5 year structural and 5 year no-leak
Wind and Water Tight
5 year structural and 5 year no-leak
Economy
1 year against roof leaks
Ask about warranty terms for a refrigerated unit before you buy.
The IICL Standard, Briefly
The Institute of International Container Lessors maintains the inspection standard used to certify cargo worthy containers. IICL inspectors check structural members, weatherproofing, door function, and floor integrity against a published criteria set.
How to Choose for Your Use Case
The match between use case and grade:
Use Case
Recommended Grade
Construction jobsite tools and materials
WWT
Farm or ranch equipment storage
Economy or WWT
Household goods during renovation
WWT
Office, workshop, tap-room conversion
One-trip
Tiny home or container home build
One-trip
Long-term acreage storage
WWT
Insurance-grade documentation needed
Cargo worthy
Customer-facing placement (retail, hospitality)
One-trip
Inspecting Before You Buy
Whatever grade you select, the visual checklist is the same:
Floor. Walk it. Listen for soft spots. Look for water staining or rot. A damaged floor is costly to repair after delivery.
Door seals. Look for daylight around the closed doors from inside while a second person stays outside with the doors unlatched. Daylight means a gap in the seal.
Roof. If you can climb up safely, check for dents that pool water, rust through-spots, and obvious patches.
Corner castings. The eight corner blocks should be intact and free of major damage. They carry the entire load when the unit is lifted or stacked.
Side walls. Look for bulges, deep dents, and heavy rust patches. Surface rust is normal; structural rust is not.
Use this checklist when the container arrives.
Delivery and Grade in South Carolina
Containers are supplied and delivered by Container One.
Delivery timing depends on location, payment, weather, container availability and site access; Container One's Delivery/Dispatch department schedules the date after payment is received and the site is reviewed. Delivery areas across South Carolina:
Charleston, the Lowcountry tri-county and the sea islands, served from the Savannah depot about 109 road miles down the coast
Columbia, Lexington and the Midlands, served from the Charleston depot about 104 miles up I-26
Greenville, Spartanburg, Anderson and the Upstate, served from the Charlotte depot about 120 miles up I-85
Frequently Asked Questions About Container Grades
Cargo worthy means the container has been surveyed and certified as fit to carry freight on a ship again, which is a higher standard and comes with the paperwork to prove it. Wind and water tight means it has been retired from ocean service but is still dry inside, with sound doors, a sound roof and no daylight through the walls. Both carry a 5 year warranty. For storage on the ground in South Carolina, wind and water tight does the job and costs less. Cargo worthy is what you want if the box will ever travel loaded or if a buyer down the line will ask for the survey.
Wind and water tight is the grade to start with for storage in South Carolina. A 20ft Wind and Water Tight container delivered in Charleston starts at $2,078. Economy costs less and carries a 1 year warranty covering roof leaks only, which is a reasonable trade on a working farm or a fenced yard and a poor one on a lot where the box will be seen. One-trip is what to buy when appearance matters, when the container will be painted or converted, or when you want the longest warranty Container One offers, 10 years structural and no-leak.
The warranty depends on the grade. One-trip carries 10 years structural and no-leak. Cargo worthy carries 5 years. Wind and water tight carries 5 years. Economy carries 1 year covering roof leaks only. Refrigerated units are inspected and tested before delivery. Ask about their warranty terms before you buy.
Walk the box before the driver leaves. Open and close both doors to confirm they swing and latch, because a container set out of level on soft ground will tell you through the doors first. Step inside, pull the doors most of the way to and look for daylight at the roof line and the seams. Check the roof for standing debris and for any dent that would pond water. On the coast, look hard at the door gaskets and at any place the paint is thin, because salt air finds a coating breach faster than inland air does. Confirm the corners are sitting solidly on your blocks or gravel rather than bridging a soft spot.
It depends on what the box is for. For a fenced yard, a job site or a field, the extra cost of one-trip goes to appearance and a longer warranty, so wind and water tight is the practical choice. For a container that will sit in view on a residential lot, get painted to match a building, carry a business name, or be cut open and converted into an office or a workshop, one-trip is worth considering. Straight walls with no prior repair are easier to cut, weld and finish, and the 10 year structural and no-leak warranty goes with a box you are about to invest more money into.