What Are Rainwater Tanks Made Of?

Most modern rainwater tanks are made from polyethylene (poly), steel, or concrete. In Australia, poly water tanks are the most common because they’re lightweight, affordable, and durable. Polymaster tanks are made from food-grade polyethylene, are UV-stabilised, and are Australian-made, providing long-term, safe storage for household and farm use.

What Materials Are Commonly Used?

When you’re comparing rainwater tank materials, you’re usually choosing between poly, steel, and concrete. Each one is made differently and uses specific coatings or linings to protect water quality.

• Poly tanks: made by rotationally moulding food-grade polyethylene inside a hollow mould. As the mould spins and heats, the plastic melts and forms a single, seamless shell with no joins. UV-stabilised pigments are added so the tank resists sunlight and doesn’t become brittle, and no extra liner is required.
• Steel tanks: built from rolled galvanised or Colorbond® sheets that are joined with bolts or welds. For drinking water, they rely on either a bonded food-grade polymer coating (such as Aquaplate®) or a flexible poly liner so water never touches bare metal, helping control corrosion and taste.
• Concrete tanks: cast from cement, sand, aggregate and steel reinforcing, either precast in sections or poured in place. They may be left as raw concrete or sealed internally to reduce seepage, lime leaching and changes to water taste.

Why Choose a Poly Tank?

For most residential and many rural properties, poly offers the best balance of cost, durability and ease of installation, while being lightweight, non-corrosive and easy to position on site. That’s why many people choose Polymaster’s poly rainwater tanks, which are food-grade, UV stabilised and engineered for Australian conditions, with industry-leading warranties that give added peace of mind.

If you’re comparing rainwater tank materials, explore Polymaster’s poly tank range to find a safe, reliable solution that suits your site and water needs.

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