Avoid costly mistakes when buying a used water tank and ensure your rainwater system is clean, safe, and reliable.

In an era of rising costs and increasing interest in sustainable living, buying a used water tank might seem like a savvy way to save money. After all, a pre-loved poly or steel tank can often be found online at a fraction of the cost of a new one. But what many buyers don’t realise is that second-hand tanks can come with hidden problems — and those problems can cost you more in the long run.

From contamination risks to structural failures, here are 7 red flags you should watch out for before you commit to a used water tank — and why purchasing new from a trusted manufacturer like The Water Tank Factory is often the smarter investment.

1. Cracks, Warping or UV Damage

Poly water tanks are made from UV-stabilised plastic — but over time, Australia’s harsh sun can still take a toll. A second-hand tank that’s spent years in full sun may become brittle, warped, or develop fine cracks that are hard to spot at first glance.

Why it matters:
Cracks compromise the structural integrity of the tank, leading to leaks or catastrophic failure when filled. Warping may mean the tank no longer sits flat, affecting fittings and water flow.

Check for: spider cracks near inlets/outlets, distortion on the tank body, discolouration, and “chalky” surface texture.

2. Unclear History or Unknown Contents

You’d never drink from a glass that had previously held unknown chemicals — yet some second-hand tanks have been used to store fertilisers, diesel, or waste water without being properly disclosed.

Why it matters:
Tanks used for non-potable liquids may leach contaminants into rainwater, even after cleaning. This makes them unsafe for garden irrigation (let alone drinking, laundry or toilet flushing).

Ask for a full usage history — or avoid altogether if the history is unclear.

3. No Manufacturer Label or Warranty

Genuine water tanks should include a manufacturer’s label or embossing that identifies the brand, material, and often the manufacturing date. If a second-hand tank has no ID, that’s a problem.

Why it matters:
No label means no traceability, no assurance of quality, and no eligibility for warranty or service. You may not even know if it was made for above-ground or underground use.

Stick to tanks with clear, branded identification from trusted Australian manufacturers.

4. Damaged or Missing Fittings

Used tanks are often sold without proper fittings, lids, strainers, or overflow pipes. Even if they’re present, they may be cracked, rusted, or incompatible with modern plumbing setups.

Why it matters:
Replacing fittings can be expensive and time-consuming. Worse, poor seals or missing overflows can lead to contamination, mosquito breeding, or water loss.

Check the condition of all fittings — especially the outlet, strainer, and overflow. Missing or mismatched components are a major red flag.

5. Tank Was Relocated Without Support

Many sellers will list a tank that’s been removed from its original base and stored upright, on grass, or even sideways. Without a stable base, the tank may deform, crack, or collapse.

Why it matters:
Water tanks must be stored and transported properly — especially poly models, which can deform under their own weight if unsupported.

If it’s been moved or stored incorrectly, structural damage might not be immediately visible.

6. It’s an Old Design or Unsafe Model

Older tanks may not meet modern Australian Standards for water storage (like AS/NZS 4766 or AS/NZS 4020 for drinking water safety). Some early plastic tanks used materials that have since been phased out.

Why it matters:
New designs include thicker walls, better UV resistance, and improved safety standards. Old tanks may not hold up — literally — under today’s expectations.

Check for updated design features like reinforced outlets, even wall thickness, and food-grade polyethylene.

7. You’re Paying More Than It’s Worth

Here’s a surprising truth: many second-hand tanks are overpriced. A 5,000L used poly tank might be listed for $1,200, yet a brand new 5,000L model from The Water Tank Factory can cost just $1,160 — with full warranty and pristine condition.

Why it matters:
You’re not saving if you still need to replace fittings, clean the tank thoroughly, or deal with a short lifespan.

Always compare prices with new tanks from reputable manufacturers before deciding.

A Better Alternative: Buy New from The Water Tank Factory

When you purchase a brand-new poly or steel water tank from The Water Tank Factory, you get:

✔ Food-grade, BPA-free polyethylene or Aquaplate® steel
✔ Thick, evenly distributed walls (tested and simulated for strength)
✔ 10+10-year warranty on poly tanks
✔ Modern design, proven in Australia’s climate
✔ Fast nationwide delivery with optional pump bundles

And best of all? You’ll have peace of mind knowing your water is clean, safe, and stored in a tank that will last for decades.

Final Thoughts: Is A Used Water Tank Worth the Risk?

While second-hand water tanks might seem budget-friendly upfront, they often come with costly risks. From unseen damage to health hazards, the long-term value simply isn’t there.

For a smarter investment — and a tank you can trust — explore the 1,745+ size, style, and colour combinations at The Water Tank Factory. We’ll help you find the perfect fit for your home, farm, or business.