What size water tank do you need?
We know that a water storage scheme can dramatically reduce a utility bill, while providing that extra security during the drier spells often seen during El Niño weather periods. But which size do you go for?
The size of your water tank depends on both your intended usage and your ability to collect it. After all, what is the use of a 40,000 litre tank if you're only likely to collect half that amount throughout the year?
Conversely, in Australia, where many states rank as some of the driest regions in the world, you'll want to make sure you are able to collect as much rainwater as possible if you want to put it to good use.
If you're looking to buy a new water tank, you'll have plenty of questions, so it helps to understand how your new water tank will work.
How does a water tank collect rainwater?
As rainwater lands on your roof, your guttering will direct it into your poly water tank. This means the amount that can be collected depends on the size of the catchment area – your roof.
A larger roof often means you can go for a water tank with a greater capacity. Ideally, you'd like your tank to be at the optimum size to match both your catchment area and your intended usage.
How much water can you collect?
Your water storage potential is calculated as one litre per millimetre of rainwater that lands on each one metre² portion of your roof.
If your roof is 20m² and you live in Sydney – where annual rainfall is around 1,000 millimetres per year – you have the potential to collect and use 20,000 litres of water in an average year.
As another example, if you own a business with a particularly large building of 100m² roof area, though live in a region with only 300 millimetres of rainfall per year, a 30,000 litre water tank would be the smallest you'd want to go for.
What else is there to consider?
Each litre of water weighs almost exactly a kilogram. If you have a tank that can collect 20,000 litres of water, that means it will need to hold 20 tonnes comfortably.
Choosing a tank with exceptional quality will ensure your water storage scheme lasts for years.
This means choosing your water tank supplier carefully. For instance, Dex Australia in New South Wales is able to guide you to the right model made from a strong polyethylene resin, like Alkatuff.
By Gerald Beckton.