Do we really need to drink eight glasses a day, or is it all just a big marketing con?
A very interesting study was carried out earlier this year by sports scientists in Australia. They wanted to determine how significant rehydration with water is to an athlete's performance. They carried out a test on a number of cyclists but, crucially, gave each of them varying levels of water, including none at all.
The cyclists, rehydrated through a drip, had no idea how much water they were taking on board. The results show no differences between the performances of those who had plenty of water and those who had none.
Does this suggest our 'need' for water intake is something of a myth? Is it something we're convinced is 'good' for us without any scientific evidence?
There are about 12 brands of bottled water in Ireland and most are represented by the Bottled Water Association of Ireland, which is a division of the Beverage Council of Ireland.
You may remember when Ballygowan water was first introduced to the Irish public way back in the mid 1980s.
Gay Byrne held up a bottle of it on 'The Late Late Show' and informed us that it wouldn't be a passing fad, but that many of us would be buying water in the not too distant future.
"Buying bottles of water!", we spluttered incredulously into our mugs of tea, "Only an eejit would pay for bottled water, go on out of that," we said.
"According to figures online (Irish Guild of Sommeliers website) Ballygowan now produces around 75 million bottles of water per year.
The bottled water industry in this country is worth an estimated €250m annually.
The Beverage Council of Ireland has reported that sales of bottled water grew by 46pc over the past 10 years. (Indeed, the situation prompted one Fine Gael senator to conduct some research into drinks prices in pubs, and discovered that mineral water costs more per litre, on average, compared to stout and beers.)
We've certainly become a nation of water guzzlers, but some people appear to be hydrating themselves just a bit too much.
This water guzzling could be another example of people buying into one of the great health myths of our time: a person needs to drink eight glasses of water a day.
Worse still, excessive consumption can lead to decreases in productivity levels. How? All that time spent dashing to the toilet.
"There is a lot of mythology around the need for water consumption; a lot of it is simply made up," he says.
"You could argue that around 70 years ago the notion came about that people need to take in about two or two and a half litres of water a day.
This idea was reinforced about 40 years later and the water companies – those selling bottled water – jumped on this idea.