So you have decided to purchase a rainwater tank. One thing consumers often do not investigate thoroughly is the warranty that is supplied with the tank. You might look at different tanks and see that some have a 10 year warranty, some say 20 years and some 30 years. Does this mean that the tank with a 30 year warranty is better than one with a 10 year warranty? Not necessarily. There are many tank manufacturers and their warranty terms and conditions are not identical, so if the issue of the tank’s warranty is important to you, make sure to always read the manufacturer’s warranty carefully when considering buying a rainwater tank.


But before considering the warranty when buying a tank, you must base your decision on your particular situation, and whether the tank will meet your needs. Rainwater storage tanks can be manufactured using several different materials, food-grade polyethylene, aquaplate steel, stainless steel and concrete. They are made in a range of shapes and sizes, and can be installed above ground, under decks or underground. All these factors can affect the suitability of the tank for your needs. And that is the most important thing to get right. Each manufacturer treats their warranty as part of their product and part of their marketing offer. The length of the warranty and it’s terms and conditions not only reflect the different properties and durabilities of individual materials and designs, but also what that manufacturer wants to say to prospective customers. For example, a steel tank may have a 20 year warranty against corrosion while a stainless steel tank may have a 30 year warranty, again against corrosion, but this has to be measured against the higher cost of this latter material. The warranties offered on polyethylene tanks vary from a 10 year warranty to a 25 year warranty but generally these warranties are not exactly the same. The 10 year warranty will, from most manufacturers, be a “Replace or Repair” warranty while the longer 20 or 25 year warranties are Pro-Rata warranties. So what are the differences? Pro-Rata warranties mean that the obligation of the manufacturer to fix or replace the tank reduces in line with the time remaining under the warranty. As an example, if you have a 5 year old tank with a 20 year pro-rata warranty, the manufacturer may only be liable for 75% the cost of the repair or replacement. If the claim is accepted after 15 years, the manufacturer’s liability will only be for 25% of the repair or replacement cost. On the other hand, with a “Replace or Repair” warranty, as long as the problem falls within the manufacturer’s Terms and Conditions, including the length of the warranty, they will replace or repair the tank entirely at their cost. So as well as understanding that the kind of tank you choose may affect the length of a warranty, you must also look carefully at the kind of warranty you purchase.