Dr Deane Hutton - The Cost of Water

COST OF WATER

If you ever get the chance to travel to space, you will discover, when you look back at Earth, that our planet looks blue. 70% of the Earth's surface is covered with water, giving the "blue planet" its characteristic colour. However, most of that water is salty - the oceans. Only 2.5% of Planet Earth's water is fresh and most of that is tied up as solid water in ice and snow. A tiny fraction is all that is available for all the living plants and animals which need fresh water to survive. It is a rare and precious resource. But how much does a glass of water cost? I'm glad you asked!

The answer to that question depends on where you are on Planet Earth. Imagine that you have a large square box with a one metre by one metre base and one metre high. It's a cubic metre. Now imagine that the box is filled with water. That cubic metre of water, or a thousand litres, would weigh exactly one tonne. What could you do with that much water? Well, if you keep your showers reasonably short and your baths reasonably shallow you are using about 50 litres of water for each shower or bath. So you could shower or bathe 20 times. Alternatively, you could use your cubic metre of water to flush the toilet 200 times or to provide 4,000 glasses of drinking water. But how much would your cubic metre of water cost?

In Australia, we are charged approximately $2.50 for a cubic metre of water. This charge includes collecting it, purifying it, delivering it to our taps, and taking away what we waste or flush down the drain. That's very cheap! In Denmark, they pay much more - $7 per cubic metre. In Mexico, they pay much less - 55 cents per cubic metre. In Ireland, tap water is free! The cost of a glass of water in Australia works out at less than one-tenth of one cent per glass. (Compare that with the cost of a bottle of water from the supermarket or delicatessen!)

So we could say that tap water for drinking is almost free. But really, the the low cost of water is a distortion. Taxes and other subsidies, in most countries, make water delivery charges cheaper than the real cost. Perhaps we should be willing to pay more for our water. If we did, we might value water more and waste it less. We can make a start by making sure we don't leave taps running unnecessarily in the bathroom, kitchen or garden and by fixing all leaking taps. Not only will we be saving water, but also we will be reducing the water delivery and removal costs. That will save energy. And that's good news for Planet Earth.