More than 70 percent of the Earth's surface is covered by water, but less than 1 percent of it is actually drinkable. With much of that drying up through desertification or becoming too contaminated for human consumption, it's clear that rethinking old water-use habits is a really important part of greening the future.

A few weeks ago I started collecting practical tips related to green living: reducing electricity usage (and consequently budget, too), reducing carbon emmissions, reducing water usage, saving the environment, healthier living - that kind of thing. A number of them are common knowledge that we've heard before, but inbetween there are some real gems that have made an impact on my daily routine.

Once I've collected 100 tips (I'm currently at 78) I'll be packaging them into easily-digestible and user-friendly formats for distribution across the web - PDFs, wallpapers, screen savers, etc. The idea for this little project, quite obviously, is to do my little bit for the environment by sharing what I've learnt. I'm a bit of a treehugger that way!

So anyway, apart from just sucking the data from various sources, I'm also doing a little bit of research on each tip to give them more weight. I just started with bottled water... yikes!

Consider the following:

• In terms of price versus production cost, bottled water puts big oil to shame. The Wall Street Journal, after seeing the incredible demand for bottled water, is considering it the next best thing to oil and gold. Fresh water is becoming humanity's most precious resource.
• It takes water to make a bottle: if a container holds 1 litre it requires 3-5 litres of water in its manufacturing process.
• Worldwide some 2.7 million tons of plastic are used to bottle water each year. The plastic most commonly used is polyethylene terepthalate (PET), which is derived from crude oil. That's a lot of barrels of oil going to waste.
• The manufacture of every ton of PET produces around 3 tons of carbon dioxide (CO2). Bottling water created more than 2.5 million tons of CO2 in 2006.
• Bottled water produces up to 1.5 million tons of plastic waste per year. Worldwide, up to 90% of bottles end up in landfills where they'll take as long as 1000 years to decompose.
• Bottled water is typically printed with expiration dates. Even if the water itself is pure, a plastic container may leak chemicals such as phthalates or Bisphenol A into the bottled water.
• With no residual disinfectant present in bottled water (it's only disinfected at source), microorganisms are free to grow and multiply in the water once it leaves the source. As a result, it has been shown that microorganisms grow in the bottles after bottling and while they stand on shop shelves.
• 25% of bottled water is just reprocessed tap water.
• It distracts from the brass ring of public health: the construction and maintenance of safe municipal water systems.

In South Africa, our tap water compares favourably with countries such as Canada, a leader in the field of managing the quality of tap water (see SA tap water passes the taste test). According to some sites, our tap water quality is third best overall in the world and we're one of only 12 countries with potable tap water.

Furthermore, a litre of bottled water purchased at a supermarket costs approximately R10. To fill a 1 litre bottle from your kitchen tap costs less than 1 cent!