Potential customers often ask us, "What size water storage tank do I need?" At first glance, it might look like one question with a range of complex answers. However, at Promax, we prefer to explain things in simple terms, so we will sum it up in one response: buy the biggest tank possible.
Why No One Regrets Extra Capacity
In our experience, no one has ever complained that their water tank is too big. Extra capacity means more water, and we know our customers always find a way to use it. A prime example is in our increasingly drought-stricken regions, where people can access the rainwater they have collected in their storage tanks and keep their lawns and gardens alive through frequent watering. There is no such thing as too much water in dry areas, and therefore no such thing as too much tank volume. The tank that looked generous in winter is the tank you are grateful for in February.
The Cost of Going Too Small
That is just one case where having access to an abundant water supply is better than the alternative, which is managing a limited amount of water where you must restrict how much you can use. The latter happens when you buy a tank that is too small for your requirements. It just does not capture as much of that beautiful rain. Rain that lands on the roof when the tank is already full is gone, and no amount of careful use afterwards brings it back. If that is the case and you need more water, you will need to buy another tank, which means making the same decision twice and paying for it twice.
If you are buying a Promax water tank and contemplating how big it should be, keep these three things in mind.
Budget: Where the Extra Litres Are Cheap
Money doesn't grow on well-irrigated trees. We know your budget will probably determine your final choice. But that doesn't necessarily mean you should buy the smallest and cheapest tank. For example, the price differential between a Promax 25,000-litre tank and a 30,000-litre tank is minimal. It will be easier and more cost-effective to invest just a little more to give you the capacity you require, rather than face the prospect of buying another tank down the track. Meanwhile, our XPRESS water tanks might not have all of the features of our ENDURO corrugated storage tanks, but they come in the same sizes. It is a very affordable option when you decide to upsize your investment, and we set out the differences in ENDURO vs XPRESS.
Footprint: How Much Space You Really Need
You might not have acres of space for your new tank, particularly if you're a residential customer. We all know that New Zealand home sections are getting smaller, especially where new builds are concerned. But Promax water tanks combine capacity with compact design, so you may be surprised how much volume you can have at your place. It is worth measuring the space you actually have before you rule a size out. Capacity is a function of height as well as ground area, so the patch of ground a tank occupies is often smaller than people picture when they hear the litres.
Council Requirements: Check Before You Buy
If you live in a rural area, did you know your council may demand that you have 45,000 litres of water on hand for firefighting purposes? A requirement like that can settle the sizing question before any of your own preferences get a look in. It's just one example of how council requirements could be a huge factor when deciding on tank size, and requirements are not the same everywhere, so you must always check with the local council before buying any water tank. Where a firefighting supply is required, there is also the separate question of how the fire service draws that water, which is what a fire service kit is for.
Putting a Number On It
Everything above is a rule of thumb, and rules of thumb have limits. If you would rather put an actual number against your own situation, our rainwater tank size calculator will do the arithmetic for you, and calculate capacity walks through the method behind it. Use whichever suits you, then apply the advice above and round up. A calculator tells you what you need. This article is about what you will wish you had. Those are rarely the same number.
The Bottom Line
Let us again state the obvious: the bigger the tank, the more water it will hold. As we have already said, you can never have too much water. So when the question turns to what size water tank you require, always go for the biggest option you can fit, afford and get past the council. Take it from us, you will have no complaints if you do. You can see the upper end of what we make in the large water tanks range.
Contact us for further information and advice to help you make the right decision.