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Conex Box in Washington: A Complete Guide for Washington Buyers
Conex box, shipping container, storage container: the words get used interchangeably. What changes from one Washington order to the next is the size, the grade and the delivery route.
The word conex (sometimes spelled CONEX) is short for "container express," a term coined by the United States military in the 1950s for a standardized steel shipping container used to move equipment and supplies during the Korean War. The original CONEX boxes were 8.5 feet by 6 feet by 6.8 feet, much smaller than today's intermodal units, but the principle was identical: a stackable, lockable, weatherproof steel box that could move by truck, rail, or ship without unpacking.
By the late 1960s the commercial shipping industry had standardized on 20-foot and 40-foot intermodal containers, the units you see on every cargo ship and rail line today. The military term stuck in everyday speech. Many people still call any large steel storage box a conex, even when the unit is technically an ISO shipping container or a purpose-built storage container.
Whichever name is used, the container is a corrugated steel box, 20 or 40 feet long, with cargo doors on one end.
Conex Box vs Shipping Container vs Storage Container
The vocabulary lines up like this:
Conex box. Originally a military-spec container. In modern use, a colloquial name for any steel shipping container used for storage. Most commonly applied to 20-foot and 40-foot units in residential and contractor settings.
Shipping container. The technical term for an ISO-standard intermodal container. These are the units that cross oceans on cargo ships. They are built to ISO 1496 specifications, which dictate dimensions, lifting points, and structural strength.
Storage container. A general retail and rental term used by ground-storage companies. Often refers to the same intermodal unit, but the phrase also covers purpose-built ground-level containers that have never seen ocean service.
If you are shopping for storage, the difference rarely matters. The same physical unit can be sold as any of the three. What matters more is the size, the condition grade, and the delivery logistics.
Standard Conex Box Sizes
There are three standard sizes:
20-foot standard. Length 20 ft, width 8 ft, height 8 ft 6 in. Interior floor about 19 ft 4 in by 7 ft 9 in, with 7 ft 10 in of height.
40-foot standard. Length 40 ft, width 8 ft, height 8 ft 6 in. Roughly 2,350 cubic feet, double the 20-foot. Best for contractors, farms, and businesses.
40-foot high cube. Length 40 ft, width 8 ft, height 9 ft 6 in. The extra foot of headroom adds about 350 cubic feet of usable space, which matters when you store racked goods or tall equipment.
Specialty sizes (10-foot, 45-foot, refrigerated, double-door, side-opening) exist but are less common.
Common Uses by Industry
In Washington, containers can serve these industries:
Tree fruit and the packing houses that move it. Apples are grown in Yakima County, and the orchard belt runs from the lower Yakima Valley north through Wenatchee, Cashmere, Entiat, Chelan, Brewster and Okanogan. Apples, cherries and pears all run on seasonal storage that has to lock and stay dry.
Hops and wine. The Yakima Valley is a hop growing region, and Washington's wine country runs from the Yakima Valley across Red Mountain and the Horse Heaven Hills to Walla Walla and up to Lake Chelan. Harvest equipment, barrels, bottling supplies and trellis hardware can need dry, lockable storage in places with no spare building.
Aerospace and its supplier base. Widebody assembly at Everett, the narrowbody line at Renton and a deep machine shop and fabrication base through Auburn, Kent, Frederickson, Arlington and Spokane form Washington's aerospace manufacturing base. The tooling, fixtures and parts those shops hold can go in a 40ft high cube, which is about 8 ft 10 in tall inside.
Timber and wood products. This sector includes mills, log yards and reload operations around Longview, Aberdeen, Hoquiam, Raymond, Morton, Randle, Darrington, Colville and Kettle Falls, plus the private timberland behind them. A lockable steel box can sit at a landing, equipment yard or gate a long way from any paved road.
Ports, marine trade and the fishing fleet. This sector includes the Northwest Seaport Alliance at Seattle and Tacoma, the ports of Longview, Vancouver, Grays Harbor and Everett, and a commercial fishing fleet that works out of Ballard, Bellingham, Blaine, Westport and Neah Bay. Gear, nets, crab pots, spare hardware and off-season equipment can be stored in a container on the waterfront.
Columbia Basin row crop and food processing. This sector includes potatoes, onions, corn, mint and timothy hay grown across Grant, Adams, Franklin and Benton counties, and the processing plants around Othello, Warden, Connell, Pasco and Richland. The hay export trade runs out of Ellensburg and the Columbia Basin toward the ports.
Dairy and berries in the northwest counties. Whatcom County has a dairy industry and grows red raspberries for processing, with blueberries alongside them, from Lynden and Everson out through Ferndale. Skagit County adds seed crops, potatoes and tulip bulbs. Wash stations, cooler yards and field crews can need seasonal storage that stands up to a wet winter.
Dryland wheat on the Palouse and across the wheat counties of the Columbia Plateau. Whitman, Lincoln, Adams, Garfield, Columbia and Walla Walla counties are dryland wheat counties, and equipment, parts and inputs can be stored at the farm rather than in town because town can be a long drive away.
Hydropower, utilities and the Hanford cleanup. This sector includes Grand Coulee Dam and the string of dams down the Columbia and the Snake, the public utility districts that grew up around them, and the long running environmental cleanup at Hanford outside Richland. Utility contractors, line crews and cleanup subcontractors run laydown yards, where a container can hold tools and materials.
Data centers and the construction that follows them. Data centers have been built in Grant, Douglas and Chelan counties around Quincy, Wenatchee and East Wenatchee, and a build like that can use containers for tools and material from site work through fit out.
The military installations and the contractors around them. The installations include Joint Base Lewis-McChord in Pierce County, Naval Base Kitsap at Bremerton and Bangor, Naval Air Station Whidbey Island at Oak Harbor, Naval Station Everett and Fairchild Air Force Base west of Spokane. The civilian contractors who work on and around those bases can keep tools and materials in secure storage.
Construction, remodeling and the trades. Framers, roofers, electricians, excavators, restoration crews and remodelers in Seattle, Tacoma and Spokane can keep tools and materials locked in a steel box on a job site.
Common uses:
Tool, chemical, and equipment storage at working yards. Steel walls, lockable doors, and on-site placement make a conex a practical substitute for a built shed, a fenced compound or a temporary office.
Weather-event storage for documents, heirlooms, and inventory.
Construction jobsite storage on long-cycle builds. Project-driven needs where timing, access, and short-term affordability all matter.
Acreage and farm storage. Permanent storage for the things a garage or barn cannot fit.
How to Choose the Right Conex Box
Three questions narrow the decision quickly:
How much space do you need? List what you intend to store. A 20-foot unit works for household goods during a renovation, materials for a residential framing job, or a few pallets of stock. A 40-foot unit doubles that. Compare the list with the container dimensions before you choose.
How clean does the interior need to be? If you are storing tools, equipment, or boxed goods, a used wind-and-water-tight unit is fine. If the unit will be converted to an office, a workshop, or a clean storage space, a one-trip unit saves the cost of repainting and floor refinishing later.
Will it move? If the container will sit on a single property for the whole life of its use, buying makes sense. For a project that ends in a few months, compare the cost of renting from a rental company with the cost of buying. Our rent vs buy guide walks through the crossover math.
How Delivery Works in Washington
Conex boxes are delivered on a tilt-bed (sometimes called a roll-off) truck. The driver tilts the bed up, and the container slides off onto your placement site. Delivery follows this sequence:
Site assessment. Container One reviews the access route, the placement spot and the overhead clearance before scheduling. A 20-foot delivery needs 110 feet of straight clearance. The truck needs at least 15 feet of height to drive, at least 22 feet of height along the entire unloading path, and at least 10 feet of width. A 40-foot delivery needs 130 feet of straight clearance.
Surface check. Concrete, asphalt, gravel, hard-packed dirt, and grass all work. Soft, waterlogged, or steeply sloped ground may need preparation.
Final placement. The driver sets the container down on the prepared spot.
Container One's Delivery/Dispatch department schedules each delivery after payment and site review. Delivery areas across Washington:
Greater Seattle, the Eastside and the South Sound, including King, Snohomish, Pierce and Thurston counties
The North Sound and the Skagit and Whatcom valleys, and southwest Washington down Interstate 5 to Clark County
Everything over the Cascade crest, from the Yakima Valley and the Columbia Basin through to Spokane, 279 road miles from the depot
Permits and Local Rules
Permit rules depend on the municipality. Before ordering, check with your local building or planning department, and verify HOA rules if they apply. The permit guide for this state covers the questions to ask: container permits in Washington.
What a Conex Box Costs in Washington
Pricing is ZIP-specific, because delivery is part of the price. Washington delivered pricing: starting at $2,889 for a 20ft Wind and Water Tight container delivered in Seattle. Prices as of 2026-08-06.
If you would rather spread the cost, rent-to-own is available through a third-party partner, My Container Rental.
Frequently Asked Questions About Conex Boxes
Conex is short for Container Express, a United States military term from the 1950s for the reusable steel boxes that moved supplies. The name stuck long after the original program ended, which is why some contractors and farmers still say conex box while the freight industry says intermodal container and the storage industry says storage container. For buying purposes the three words describe the same thing.
For anything you are likely to buy, yes. Both describe a corrugated Corten steel box, 20 or 40 feet long, with cargo doors at one end, built to keep wind and water out. The words that actually change what you receive are the grade and the size, not which of the three names the seller happens to use.
Three sizes are the standard storage options in Washington. A 20ft is 160 square feet on the ground and fits driveways, alley approaches and tight city lots. A 40ft is 320 square feet and gives you one long room. A 40ft high cube is the same footprint with about a foot more interior height, which leaves headroom after ceiling insulation and a raised floor. If you plan to insulate and finish the inside, start with the extra headroom.
A tilt bed truck backs in, raises the bed and slides the container off, so it needs a firm, reasonably level straight run behind the drop point and clear space overhead for the bed to rise. That overhead requirement matters in Ballard, Wallingford, Capitol Hill and the older blocks of Tacoma and Spokane, where the approach can be an alley under trolley wire, power lines and a mature street canopy. Seattle's own permit memo tells applicants to check overhead clearance for trolley lines, power lines and trees. Walk the route from the street to the drop spot and look up as well as around. The exact clearance figures for each size are listed on our sizes page.
Containers are supplied and delivered by Container One, dispatched from the Seattle area depot. Puget Sound matters because the Northwest Seaport Alliance, the joint marine cargo operation of the ports of Seattle and Tacoma, brings boxes into this market. Spokane runs off the same depot 279 road miles east over Snoqualmie Pass, which is why a Spokane delivered price differs from a Seattle one.