An increasingly popular product, plastic water tanks are generally made from UV-treated, impact-modified, food grade polyethylene.  

This means they’re long lasting, structurally strong (especially when corrugated) and suitable for “potable” or drinking quality water. 

Installed on a base of crusher dust or sand, they typically come with warranties for up to 25 and are available in a range of sizes, from slimline to large. 

About polyethylene 

Polyethylene is a tried and true plastic that will not break down in the sun for at least 25 years. That’s why most polyethylene water tanks come with a 25 year warranty. For added peace of mind and protection, we recommend choosing one that’s branded with a recognised standard such as an AS/NZ4766:2006 Polyethylene storage tanks for water and chemicals or AS/NZS ISO 9001:2016 Quality Management Systems – Requirements, which means the tank is made to “world’s best practice” standards.  

Manufacture 

Plastic/polyethylene water tanks are rotary moulded. The manufacturer’s steel canister mould is loaded with plastic granules or powder, closed off, and rotated over a heating source to melt the plastic. Once the plastic is melted and the canister has cooled, it’s opened to reveal the new tank.  

Some steel canister moulds have flanges down the side to make it easier to remove the tank from the mould. Tanks made in these moulds will show a line where the mould joins, however, this is not a join in the tank – it’s still made in one “piece”.   

Appearance 

Plastic water tank shapes and sizes vary according to the manufacturer. From an engineering perspective, the strongest profile design is corrugated. These designs also look like a conventional tank, which can be a positive selling point. Corrugated sides are obviously less of a concern for smaller, slimline tanks. Available in a range of colours, polyethylene water tanks are comparatively lightweight. This makes them easier to install and transport.  

Advantages & benefits 

Cost, colour, water quality, weight and ease of installation are all key selling points for polyethylene water tanks. The tanks are relatively inexpensive, they come in a range of colours, they’re designed to hold drinking quality water, and they’re lightweight and straightforward to install. Some models are also reinforced for underground installation, making them a versatile option suited to a range of sites and situations.  

The right tank for you 

As you can see, there are many reasons a plastic polyethylene water tank may be the best choice for you.  

However, regardless of whether you choose to install a polyethylene tank or not, be sure to choose one that’s the right size for your needs and property. 

You should also complement your rainwater tank with appropriate Rain Harvesting equipment to ensure the water that ends up in your tank is clean and fit-for-purpose.