Poly/Plastic tanks are among the fastest growing types of tanks. They are made from polyethylene which is UV treated, impact modified, and food grade which means it is suitable for potable (drinking quality) water. Corrugated designs are particularly strong profiles by engineering design.

Plastic tanks can be placed on a base of cracker dust or sand, and typically come with warranties of up to 25 years.

Plastic/Polyethylene tanks are rotary moulded. To make a tank the manufacturer makes a mould from steel, like a big steel canister. The canister is then loaded with plastic granules or powder, closed off and then rotated over a heating source to melt the plastic. When the plastic has melted and the canister cooled down it is opened and there is the tank. The amount of plastic granules or powder placed in the canister determines the thickness of the tank. Some steel moulds for plastic tanks have flanges down the side to make it easier to get the tank out of the mould and tanks made in moulds like this will show a line where the mould joins but it is not a join in the tank.

There are a variety of manufacturers of this type of tank around the world and there will be a stockist near you. The shapes of the tanks vary according to the manufacturer. The majority of the designs are computer generated for both strength and appearance but by far the strongest profile by engineering design is corrugated. These designs actually look like a conventional tank and can complement the home and environment well.