It's a good question. Obviously a rainwater tank will not help if there is no rain at all. The thing is that most true droughts occur inland whereas most of the population lives near the coast where it does rain.
Sure we sometimes have dry winters where we get below average rainfalls but even if you were to receive half of the average rainfall it should be enough to keep your tanks full for most of the year, if not all of it. This of course depends on the size of your rainwater tank and how much water you use but providing you have a reasonable size tank you should be right. Melbourne has some of the harshest restrictions due to low rainfall over the past few years. With a roof harvest area of 200 square metres you would collect around 80,000 litres. Melbourne also has a fairly consistent rainfall throughout the year which is great for regularly topping up your tank. From this figure we can determine that it is enough water to supply HALF of the average homes' water requirements! One small rainwater tank of around 500 litres can save around 25,000 litres of water per year.
Superwall slimline modular rainwater tanks can easily fit down the side of the house or against a wall so you don't lose valuable space. These tanks are unique to other tanks because they have a completely flat finish which can be painted or rendered to look just like any normal wall. The next question we get asked is "If it rains so much, then why do we have water restrictions?" Another good question and quite a detailed one. To put it simply, most of the water we drink is stored in dams and they are should not be the only source of water available to a city.
Dam catchment is directly affected by the amount of rain received, and period between rain. Catchment areas direct water that lands on the soil and directs it towards the dam. Often these catchment areas are further inland where drought and low rainfall is more common than the coast.
If it doesn't rain for some time then the soil in the catchment areas will dry out. When it does rain then the first rain is soaked up in the soil and does not make it into the dams. If it doesn't rain again for a while then this process repeats itself. Meanwhile the water is still being consumed and unless decent rain falls then it will simply run out. That's why it is important to get water tanks so you can take responsibility for your water usage and take pressure of mains supply. Copyright (c) 2008 Dave C.
Dave is General Manager at Superwall Systems an innovative water tank company based in Perth, Australia which produces the Supertank- The world's only structural water tank. Build your house out of water