Mystery of bottled water

00:00, Jan 18 2013

There's one thing I just don't get: bottled water. Let's call it "water-to-go" - water in small plastic bottles bought at the store to sip as we drive or to drink while we do some paperwork or on the sidelines at Saturday sport.

It's a phenomenon in developed countries for people with plenty of disposable income and enterprising businesses happy to separate them from it.

Growth in bottled-water sales has been explosive in the last decade. More than 200 billion litres were sold worldwide in 2008 (the last year for which reliable public data is available). We're certainly taken with it in New Zealand. But why?

It can't be because it's good value. Let's say you pay for tap water by volume and your cost is $1.40 per cubic metre (or 1000 litres). And to make it simple, let's say the cost of a litre bottle of water is $1.40 (mid-range in the supermarket survey I did). This puts the price of the bottle one thousand times more than tap water.

Not a bad mark-up if you can get it! Especially given that bottled water is usually nothing more than filtered tap water or water from a spring or stream that provides tap water for the locals.

If you are on reticulated water from a council at a uniform rate, the extra cost - or marginal cost as economists like to call it - of any bottle you might fill is zero. Compared to the $1.40, that's an even better deal.


If you're on a rural property and have your own bore (or catch roof rainwater), you may pay a few cents a day to run a pump for all the water you need, putting your cost of drinking water near zero.

Through good fortune and good management - hats off to water engineers nationwide - quality, safe, drinking water is generally available around the country. Where "taste" is an issue or treatment is required on a rural property, costs for a filter pale in comparison to that for water-to-go.

Bottled water has also been touted for its convenience. But what could be easier than turning on the tap? Fill a bottle at home and take it with you. Refill it whenever you run out. In the early days of bottled water, drinking it was promoted by some as fashionable, even cool.

Annie Leonard, in The Story of Bottled Water (8-minute video, check it out on YouTube), talks about "manufactured demand". (One critic was on to it, asking, "Why do they call it Arctic Water when it comes from Florida?")

But there's some backlash lately due to growing concern for the environmental impact of the product. Peter Gleick, a scientist well-known internationally for his work in water resource management, has taken a look at this and written about it in his book Bottled and Sold: The Story Behind Our Obsession with Bottled Water.

Working with a colleague at their research institute in California, he computed the energy required to bring bottled water to market. The two areas of greatest energy use are manufacture of the bottles and transportation. Bottom line: Bottled water is 1000 to 2000 times more energy-intensive than tap water production depending on the distance it travels from production to store shelf.

All this for a bottle of water and we still haven't got to the getting-rid-of-it part. Recycling the bottles is good, of course, but there is further energy to transport the empties and turn them into base material for the likes of sleeping bag fill or fleece vests.

But, sadly, more than half of all single-serve plastic water bottles never make it to recycling. No, for this lot it's off to the landfill (energy for transportation again) where they'll take up valuable space and live on for some 500 years.

One plastic bottle hardly matters. But the many billions produced, transported, used and discarded each year come with a cost. Saying no to bottled water can be one small part of saying yes to a brighter future. It all adds up.