How to choose an outdoor polyethylene tank
An outdoor polyethylene tank is chosen first by capacity in litres and then by shape, according to the space where it will go. The collection offers models of 650 and 1300 litres, in different formats: cistern, box, slim, loft and under-stairs. It is very heavy when full: 1000 litres of water weigh about a tonne, so the base must be level and load-bearing.
The types
- Cistern: the most traditional shape for storing water. You will find it, for example, in the Rototec polyethylene cistern model.
- Box: a container with a rectangular footprint (Polyethylene box).
- Panettone, Vertigo line: a model with a shape of its own, with its dedicated data sheet (Panettone).
- Slim: designed for narrow spaces. The slim water container has stated overall dimensions of W 98-122 cm, D 46-67 cm, H 105-130 cm.
- Loft and under-stairs: the names say where they go, in spaces with little headroom; check the dimensions on the data sheet (Loft, Under-stairs).
- Other formats: Kitank and the Amphora container, each with its own shape.
How to choose by job
| Situation | What to get | Why |
|---|---|---|
| Rainwater harvesting in a garden or on a building site | Cistern or box, with the largest capacity the space allows | A heavy downpour quickly fills a small tank. |
| Narrow space between buildings or along a wall | Slim | It is shallow and fits through narrow gaps. |
| Room with a low ceiling or under a staircase | Loft or under-stairs | The shape follows the available space. |
| Reserve for an irrigation system | 1300-litre cistern | More water in store between one refill and the next. |
| Small water supply for a business | 650-litre model | It takes up less space and weighs less when full. |
Before choosing, answer three questions. How much water do you need between one refill and the next? Where will you put it, and which route does it take to get there? What will it stand on? The answers decide the size, the shape and the base, in the order in which it makes sense to think about them.
The features to look at
- Capacity: 650 and 1300 litres are among the recurring values in the collection. Choose according to your real consumption plus a margin.
- Material: polyethylene, including linear polyethylene (LLDPE). It is light, does not rust and is easy to clean.
- Dimensions: length, width and height decide whether the tank fits through the access route and into the space. The values in the collection range from 50 to 160 cm.
- Cap diameter: 21 or 30 cm. A wide cap makes it easier to inspect and clean the inside.
- Connections: inlet, outlet (1 inch) and drain (3/4 inch). Check that the fittings of your system are compatible.
- Suitability for the liquid: check on the data sheet that it is suitable for the liquid you intend to store, especially for uses other than water.
Common mistakes
- Setting the tank on uneven ground or on stones: polyethylene deforms under the weight.
- Forgetting that a full tank weighs a tonne for every thousand litres.
- Choosing on litres alone without measuring the route to carry it to the installation point.
- Leaving the system exposed to frost: connected pipes and fittings must be protected.
- Connecting rigid pipes without suitable fittings: a polyethylene tank moves slightly, and the connections must allow for it.
- Not providing an overflow: excess water must have a way out.
Frequently asked questions
Do I need a base?
Yes, level, smooth and load-bearing, with no sharp edges. It must support the full tank.
Can I use it for rainwater?
Yes, it is one of the uses it was designed for, with an inlet filter and a connected overflow.
Can it be left outdoors in winter?
Yes, but the connected system must be protected from frost; with water inside, ice can damage pipes and fittings.
Does it have to be kept closed?
Yes, the lid stays closed: it stops leaves, insects and dirt from getting into the water.
How do I clean it?
Through the cap, periodically, by emptying it and rinsing the inside.
See all the models in the Outdoor Tanks collection: to choose format and capacity, request a quote or ask the AMES technicians for advice.
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