Do you know how much water is in your morning coffee? If I measure the capacity of my coffee mug, it comes to just over 250ml, which, if I add up the number of cups I consume during the day, comes to, well, let’s rather not discuss my caffeine habit. Except, even with full disclosure the simple multiplication of capacity by number of cups is incorrect - because every cup of coffee I consume contains not 250ml of water, but a massive 140 litres!

South Africans consume, per capita, 2,500 litres of water per day, but not by drinking or cooking or gardening alone. What we overlook is just how much is required for production of those goods we take for granted. Called ‘virtual water’, it determines our water footprint (visible and virtual water used) as individuals, businesses and a nation.

To produce an apple weighing around 100 grams, 70 litres of water is used. One slice of wheat bread requires 40 litres. The water footprint of a beer, 75 litres, pales in comparison to that of the hamburger that often accompanies it, which comes in at a whopping 2,400 litres. In fact, beef requires a full 15,500 litres of water to produce just 1kg.

And it’s not just what we eat and drink. One A4 sheet of 80gr paper, processed from wood, requires 10 litres of water - something to consider before printing out the joke email that will be discarded later. The global average footprint of one cotton shirt is 2,700 litres; for one kilogram it’s 11,000 litres. One kilogram of leather requires 16,600 litres of water (global average).

Does this mean I should immediately give up coffee? Perhaps, but in all honesty I am not going to. However, simply being aware of how much water goes into everything we consume can have a positive impact. Small changes make a big difference. I may not give up coffee entirely, but I can reduce my intake. If I were to cut back by just one cup a day for a year, I’d save 51,100 litres!

If you think a meal is incomplete without meat, no-one is going to expect you to embrace vegetarianism, but why not give it up for just one or two days a week? Instead of always choosing a huge, beefy burger, replace at least one with, perhaps, this delicious Portabella Mushroom Burger.

South Africa is facing a critical water shortage, and here’s the thing: those of us with who live comfortably will not be the first affected despite being the country’s biggest consumers. The poor, whose water footprints are in many cases negligible, will suffer first, giving rise to more problems than just higher prices and water cuts; these problems will affect everyone.

We waste a lot of water. My experiment earlier this year proves this. But if each of us developed just one water-saving habit, we’d be able to make a big difference. And as I’ve discovered, one habit invariably leads to more.

For more information about water footprints, visit www.waterfootprint.org