Poly vs. Steel Water Tanks: Which is Right for You?

When it comes to investing in a water tank, one of the first decisions you’ll face is what material to choose. The two most common options in Australia are polyethylene (poly) tanks and steel tanks. Both have their advantages, but the right choice depends on your property, water needs, and budget.

In this guide, we’ll compare poly vs. steel water tanks to help you decide.

A Global Poly tank situated next to a house on a semi-rural Tasmanian property.

Durability & Strength

• Poly Tanks: Made from UV-stabilised polyethylene, poly tanks are designed to withstand harsh Australian sun and tough conditions. They won’t rust or corrode, making them ideal for coastal or damp environments.

• Steel Tanks: Galvanised or Colorbond® steel tanks are known for their rigid structure and long-term strength. However, without proper maintenance, steel can corrode over time—especially in coastal or acidic soil areas.
  

Winner: Poly tanks for all-round weather resistance; steel tanks for heavy-duty applications in dry inland areas.

Weight & Installation

• Poly Tanks: Lightweight and easy to transport, poly tanks can often be rolled into position without heavy machinery. This makes installation simpler and cheaper.

• Steel Tanks: Heavier and more rigid, steel tanks often require cranes or specialist equipment for delivery and placement, adding to installation costs.

Winner: Poly tanks for hassle-free setup.

Lifespan & Maintenance

• Poly Tanks: With no seams or welds, there are fewer weak points. Properly made and certified poly tanks can last 20+ years with minimal maintenance.

• Steel Tanks: High-quality steel tanks can also last decades, but require protective coatings and regular checks for rust or corrosion.

Winner: Both can last a long time—poly wins on low-maintenance living.

Cost

• Poly Tanks: Generally more affordable upfront, especially for common household sizes (5,000–30,000L).

• Steel Tanks: Higher upfront costs, particularly for large capacities or custom-built options.

Winner: Poly tanks for value, steel tanks if you need a very large custom build.

Capacity & Design Flexibility

• Poly Tanks: Available in a wide range of shapes (round, slimline, underground) and colours to blend into your property.

• Steel Tanks: Best suited for very large rural storage (50,000L+), often only available in round designs.

Winner: Poly tanks for variety, steel tanks for mega-storage.

Environmental Impact

• Poly Tanks: 100% recyclable at end of life, made with UV-stabilised materials that reduce waste.

• Steel Tanks: Also recyclable but require more energy and resources to produce.

Winner: Both are recyclable—poly has a lighter environmental footprint.

So, Which Tank is Right for You?

If you’re after affordable, reliable, and low-maintenance storage, a poly water tank is hard to beat. They’re versatile, tough, and ideal for most Aussie homes, gardens, and farms.

If you need extra-large capacity for agricultural or commercial use, a steel tank may be worth considering.

At Global Poly Water Tanks, we specialise in AS/NZS 4766-certified poly water tanks—built tough for Australian conditions and backed by industry-leading warranties.