Overview
When shopping around for a rainwater or liquid storage tank, headlines such as “10-Year Warranty” or even “25-Year Warranty” immediately catch the eye. They give buyers peace of mind, creating the impression that their investment is protected for years to come. In present-day Australia where rising living costs, soaring fuel prices, and severe climate conditions like floods and droughts are top of mind, buyers now more than ever need to know their dollar is going toward genuine, long-term value.
However, across the Australian water tank industry, there is a significant (and often overlooked) difference between a standard warranty and a full guarantee. Many standard poly tank warranties operate on a pro-rata basis, and while the advertised length may span from 5, 10 to 25 years, the actual financial protection drops significantly with each passing year. If a failure occurs midway through the term, buyers can be left facing expensive, unexpected out-of-pocket costs for a replacement. By contrast, a Full Guarantee such as Bushmans’ 10-Year Guarantee, provides 100% complete coverage for repair or replacement throughout the entire guarantee period, without hidden formulas or unexpected out-of-pocket expenses.
In this guide, we break down how warranties and guarantees work in Australia, how to read the fine print before investing, and why a true full guarantee delivers genuine long-term protection.
| Feature | Full Guarantee (e.g., Bushmans) | Pro-Rata Industry Warranty |
|---|
| Financial Coverage | 100% full coverage for the entire period | Decreases percentage-wise every year |
| Out-of-Pocket Cost in Year 8 | $0 (repair or full replacement) | High (customer pays ~60–80% of replacement cost) |
| Headline Claim vs. Real Value | Fixed, transparent protection | Long headline years (e.g., 20–25 years) disguise diminishing protection |
| Replacement Basis | Direct replacement or full repair | Discount off current RRP based on remaining fractional percentage |
Year-by-Year Financial Coverage Breakdown: Full Guarantee vs. Pro-Rata Warranties (%)| Year | Bushmans 10-Year Guarantee (%) | Typical 20-Year Pro-Rata Warranty (%) | Typical 25-Year Pro-Rata Warranty (%) |
|---|
| 0 | 100% | 100% | 100% |
| 1 | 100% | 97% | 97% |
| 2 | 100% | 90% | 95% |
| 5 | 100% | 60% | 75% |
| 10 | 100% | 25% | 40% |
| 11 | 0% | 20% | 35% |
| 15 | 0% | 10% | 20% |
| 20 | 0% | 0% | 10% |
| 25 | 0% | 0% | 0% |
What is a Pro-Rata Water Tank Warranty?
A pro-rata water tank warranty means the manufacturer’s financial contribution drops over time. The longer you own the tank, the less the manufacturer pays toward a replacement if something goes wrong. While a manufacturer might promote a “20-Year Warranty”, the fine print says otherwise. Instead of covering a full replacement if a defect occurs, the manufacturer pays less as your tank gets older – which leaves you as the buyer to cover the rest out of pocket.
How Pro-Rata Coverage Works
Under a standard pro-rata warranty, financial protection is divided into distinct stages based on product age:
Years 1–2: The manufacturer typically covers 100% of repair or replacement costs for verified manufacturing defects.
Years 3 and Onward: Financial coverage reduces by a fixed percentage each year (often dropping 5% to 10% annually).
Late-Term Coverage: In the final years of the warranty, the manufacturer’s contribution often drops to a small fraction of the replacement value.
(Note: In Australia, manufacturer warranties operate alongside your statutory rights under Australian Consumer Law, which guarantees that products must be of acceptable quality and fit for purpose)
Real-World Example: The $3,000 Tank Failure
To understand the financial impact of a pro-rata warranty, consider a scenario where an Australian buyer purchases a $3,000 poly water tank with a typical 20-year pro-rata warranty.
If the tank suffers a structural failure due to a manufacturing fault in Year 12:
The Formula: Because the tank is 12 years old, the pro-rata formula has reduced the manufacturer’s liability by a fixed percentage per year over 12 years (often a 60–70% reduction).
The Coverage Gap: The manufacturer may only cover 20% to 30% of the replacement cost based on the current retail price.
The Out-of-Pocket Cost: The buyer must pay the remaining 70% to 80% out of pocket to receive a replacement unit, plus additional freight and installation charges.
What is a Full Poly Tank Guarantee?
A full poly tank guarantee is a binding commitment where the manufacturer covers 100% of the financial cost to repair or replace a defective tank throughout the entire guarantee period.
Unlike a pro-rata warranty, a full guarantee provides static, complete financial protection from the first day of ownership until the last.
Key Advantages of a Full Guarantee
Fixed 100% Protection: A 10-year full guarantee offers the exact same 100% financial protection in Year 9 as it does on Day 1. If a manufacturing failure occurs, coverage does not reduce over time.
Complete Financial Protection: Buyers face no unexpected “gap payments,” sliding-scale contributions, or hidden formulas if a failure occurs during the guarantee period.
3 Questions to Ask Before Buying a Poly Water Tank in Australia
Before investing in a rainwater or liquid storage tank, ask these three critical questions to ensure you understand the true value of your coverage:
“Is this coverage a full guarantee or pro-rata warranty?” Always ask if the financial coverage reduces over time. E.g If a supplier advertises a “25-Year Warranty,” request the written terms to confirm whether it maintains 100% coverage or operates on a sliding scale.
“What percentage of the replacement cost am I responsible for in Year 5 or Year 10?” This reveals your exact out-of-pocket expenses midway through the lifespan of your tank.
“Does the coverage apply to the full tank or only specific parts?” Confirms that the poly tank shell is fully guaranteed, and clarifies what separate terms apply to fittings and accessories.
Frequently Asked Questions
Is a 25-year pro-rata warranty better than a 10-year full guarantee?
No. A 10-year full guarantee provides 100% financial coverage for the entire 10-year period. A 25-year pro-rata warranty typically reduces coverage quickly, leaving the customer responsible for most of the replacement cost after the first few years.
Does Bushmans offer a 100% full value guarantee or a pro-rata warranty on water tanks?
Bushmans provides a 10-Year Full Value Guarantee on standard aboveground polyethylene water tanks, NOT a pro-rata warranty. Bushmans retains 100% full replacement and repair coverage across the entire decade so you are never left out of pocket for a manufacturing defect. Read the complete Bushmans 10-Year Warranty conditions here to see how our full coverage protects your investment.
Why do poly tank manufacturers use pro-rata warranties?
Pro-rata warranties allow manufacturers to advertise long headline figures (such as 20 or 25 years) while significantly limiting their financial liability if a product fails later in its life cycle.
Are fittings, pumps, and strainers included in the 10-year guarantee?
No. Third-party accessories carry separate supplier warranties (typically 1 to 5 years). The 10-year full guarantee specifically protects the poly tank shell itself.