Guide · Building
Shipping Container Pool
Yuri Kan Checked against 23 of 88 published sheets Updated
A shipping container pool is a 20 or 40 ft box reinforced with steel ribs, lined, and fitted with filtration at one end. Take the inside of a 20 ft (5.898 × 2.352 m), set aside about a metre for the filtration bay, and the swim zone is about 4.9 × 2.352 m; at 1.2–1.5 m of water that is 14,000–17,000 L. A 40 ft gives an 11.0 m lane holding 31,000–39,000 L. Modpools, a maker that publishes its prices, lists its 20 × 8 ft model at $49,500 and its 40 × 8 ft at $68,000 before shipping and installation, and puts a typical whole project at $57,000–145,000+. One number explains the logistics: 39,000 L of water weighs 39 tonnes, past the 28,800 kg payload most published sheets print for a 40 ft — container pools always travel empty and are filled on site, sitting on a slab or piers, never on the truck.
The pitch is genuine: a lap-shaped pool that arrives finished on a truck, cranes onto a prepared base, and swims the same week. But a shipping container was engineered to keep water out and carry load on its floor — turning it into a vessel that holds 14–39 tonnes of water pressing outward is real structural work, and the honest numbers are worth knowing before you compare quotes.
This guide computes the swim lengths, litres and weights from the actual inside dimensions, as most published sheets print them — 5.898 × 2.352 × 2.393 m for a 20 ft, 12.032 × 2.352 × 2.393 m for a 40 ft — and then walks the structure, installation options and costs. The filtration bay and the water depth are this page’s stated assumptions; the depths and prices are a maker’s, from one sheet (Modpools).
Pool dimensions: what a 20 and 40 ft box actually gives you
The section drawing above shows the layout this page counts with: the last metre of the box is a filtration bay — pump, filter, optional heater and chlorinator behind a bulkhead — and the rest is water. That leaves a swim zone of about 4.9 m in a 20 ft container and about 11.0 m in a 40 ft, both 2.352 m wide, the full inside width. It is a one-swimmer lane, sized like a short lap pool rather than a family free-form pool.
Depth is a design choice, not the full 2.393 m inside height. This page counts with 1.2–1.5 m of water (1.35 m in the worked example); Modpools fills its 20 and 40 ft models to 1.37–1.42 m (4′6″–4′8″).
That water depth is deep enough to swim and stand, and shallow enough to keep weight, bracing and safety manageable. Some designs use the full-height end for a plunge section; diving depth is not achievable in this format.
| Base box | Inside L × W | Swim zone | Water depth | Volume |
|---|---|---|---|---|
| 20 ft | 5.898 × 2.352 m | ~4.9 × 2.352 m | 1.2–1.5 m | ≈14,000–17,000 L |
| 40 ft | 12.032 × 2.352 m | ~11.0 × 2.352 m | 1.2–1.5 m | ≈31,000–39,000 L |
Checked : outside sizes set by ISO 668, read in IS 6566:2001, GOST R 51876-2008 and GOST R 53350-2009; every other figure against 23 published sheets of 19 lines, lessors and makers. A sheet agrees within ±5 mm, or ±2 % for a mass and ±1 % for a volume; a maximum gross is a rating and must be the same. Every figure and its sources
Water volume: how many litres a container pool holds
Volume is a straight multiplication of the wetted box:
- 20 ft: 4.9 m swim length × 2.352 m width × 1.35 m depth ≈ 15.6 m³ ≈ 15,600 litres, and 1.2–1.5 m of water spans 14,000–17,000 L.
- 40 ft: 11.0 × 2.352 × 1.35 ≈ 35.0 m³ ≈ 35,000 L, spanning 31,000–39,000 L across the same depths.
Those litres drive the running costs. Warming the 40 ft pool’s 35,000 L by 10 °C takes about 407 kWh of delivered heat (181 kWh for the 20 ft).
A 40 ft pool also needs more than twice the pump, filter and chemical throughput of a 20 ft. That is the main argument for the smaller box in cool climates: less than half the water heats more than twice as fast for the same heater.
The weight paradox: why pools ship empty
Here is the number most brochures skip. Water is 1,000 kg/m³, so a filled 40 ft pool carries 31–39 t of water — but the box’s payload is 28,800 kg on most published sheets. A filled 40 ft container pool exceeds the rating of the very container it is made from.
The container’s corner-post structure assumes cargo resting on the floor, not fluid pressing on the walls. Even a 20 ft’s 14–17 t, while under its 28,250 kg payload on paper, is nothing a truck or crane will move as liquid cargo.
The consequence is universal: container pools are transported empty and filled on site. The bare box weighs about 2,230 kg (20 ft) or 3,700 kg (40 ft) by the published sheets (a 20 ft runs 2,080–2,570 kg). That is before ribs, liner and plant go in: an ordinary crane lift (see moving a container).
Since the full weight of the water then bears on the ground for good, the pool sits on a reinforced concrete slab or engineered piers designed for that load; bare gravel is not enough. Base options and loads are covered in the foundation guide.
Structure: why the walls need steel ribs
A container wall is 1.6 mm corrugated sheet on the makers’ sheets, engineered as a shear web for stacking loads in the wall’s own plane — not for pressure perpendicular to it. Water 1.35 m deep pushes on the foot of the wall at about 13.2 kPa (density × gravity × depth), a distributed outward load the corrugations were never asked to carry. An unreinforced container filled with water visibly bows its side walls and works its welds.
Every serious container pool conversion therefore builds two layers before it holds water:
- A welded rib cage: vertical steel box sections tied between the bottom and top rails at close spacing, sized by the builder, often with a stiffened top rim that doubles as the coping.
- Waterproofing: a welded reinforced-PVC or fibreglass liner, or an epoxy-coated fully welded steel tank inside the box.
When comparing quotes, ask specifically what reinforcement and liner system is included. It is where a cheap quote and a dear one differ, and the thing that fails if omitted.
Above-ground, in-ground, or in between
- Above-ground is the format’s home turf: the box sits on its slab, its own wall becomes a built-in safety barrier, plumbing stays accessible, and many designs glaze one wall as a window. Access is by stairs and a small deck. It is also fully reversible — the pool cranes out as easily as it arrived, which matters for rentals and resale.
- In-ground installation buries the same box in an excavation: visually a conventional pool at conventional excavation cost. It adds two engineering notes: external corrosion protection (bitumen coating and drainage against soil moisture) and groundwater management, since an empty steel tank in wet ground wants to float.
- Semi-recessed — sunk part of its height, with a deck at coping height — splits the difference and keeps the filtration bay serviceable.
Cost: container pool vs concrete
What one maker prints, at March 2026 prices: Modpools lists its 20 × 8 ft model at $49,500 and its 40 × 8 ft at $68,000, the base unit with pump, filter and heater fitted. That price is before shipping ($2,500–11,500 from its factory in British Columbia) and before site preparation, crane and installation ($20,000–60,000+, decking and landscaping included).
Modpools’ typical whole project is $57,000–145,000+, and its own itemised do-it-yourself install in Texas came to $12,950 without the pool. A build from a used box ($1,700–2,800 for the 20 ft shell) cuts the cash cost further in exchange for the welding, lining and plumbing labour.
The same maker puts a concrete pool at $50,000–120,000+ for the pool and $80,000–150,000+ for the project, with months of siteworks — a seller’s comparison, not a pool builder’s quote. The container pool’s case and its limits are equally clear:
- For: speed (swimming within days of delivery), a small-footprint lap shape, and relocatability.
- Against: a fixed 2.352 m inside width, a lane rather than a lagoon, and steel that must be maintained like steel.
Permits and safety: what a container pool must pass
In most US jurisdictions a pool as deep as this one needs a building permit plus barrier compliance. The barrier is of the height the local code sets, with self-latching gates; an above-ground container’s own walls often satisfy it where a ladder-removal or gated-stair detail is used.
Electrical work must meet NEC Article 680 — bonding of the steel shell is not optional in a pool that is steel — and some areas add setback and drainage rules. Ask the building department for the depth that triggers a permit and the barrier height it wants before booking the crane.
Frequently asked questions
How much does a shipping container pool cost?
Modpools, a maker that publishes its prices, lists its 20 × 8 ft container pool at $49,500 and its 40 × 8 ft at $68,000 before shipping and installation, and puts a typical whole project at $57,000–145,000+ (March 2026 prices). Shipping adds $2,500–11,500 and site work, crane and installation $20,000–60,000+; the same maker puts a concrete pool at $50,000–120,000+.
How much is a 40 ft container pool?
Modpools lists its 40 × 8 ft model at $68,000 before shipping and installation; a 40 ft box holds 31,000–39,000 L in an 11.0 m swim lane at 1.2–1.5 m of water. Running costs scale with the water: it needs more than twice the heating and chemical throughput of a 20 ft pool.
Are container pools worth it?
If you want a lap-style pool fast, on a small or awkward site, or one you can take with you — yes: it swims within days of delivery, and Modpools’ 20 × 8 ft model at $49,500 sits below the $50,000–120,000+ the same maker puts on a concrete pool. If you want width, a free-form shape or diving depth, no: the format is locked at 2.352 m wide and about 1.5 m deep.
Can I build a container pool myself?
Structurally yes, trivially no. The box costs $1,700–2,800 used, but you must weld internal ribs (the 1.6 mm walls bow under water pressure), install a proper liner, cut and plumb the filtration bay, and meet pool electrical code including bonding the steel shell. Competent welders save part of the factory price; everyone else should buy it built.
What are the drawbacks of a container pool?
Fixed 2.352 m inside width (a lane, not a lagoon), a practical depth of about 1.5 m, steel that needs corrosion care at cut edges and fittings, mandatory reinforcement done properly, and higher heat loss than an in-ground pool unless insulated. It is a specific shape of pool, not a cheaper version of every pool.
Do I need a permit for a container pool?
Almost always — in most US jurisdictions the 1.2–1.5 m of water a container pool holds triggers pool permitting: barrier rules (fencing at the height the local code sets, or equivalent — the pool’s own walls often qualify), NEC Article 680 electrical compliance with the shell bonded, and sometimes setbacks. Ask the building department before booking delivery.
How long does a container pool last?
No maker we read prints a design life; what ends a container pool is corrosion of its 1.6 mm steel walls at cut edges and penetrations, so inspect and touch up coatings yearly. The Corten shell outlives the wet parts: the liner and the pump are replaced during the pool’s life.
Can you heat a shipping container pool?
Yes — warming a 20 ft’s 15,600 L by 10 °C takes about 181 kWh of heat and a 40 ft’s 35,000 L about 407 kWh, and Modpools fits a heater as standard on its 20 and 40 ft models. The steel shell sheds heat faster than buried concrete, so in cool climates insulation under the liner and a cover matter more than heater size; a 20 ft’s smaller volume makes it the cheaper pool to keep warm.