The Conversation reports:
Drinking enough water is very important during long periods of physical activity or recreational pursuits. But there are rare instances when too much fluid intake can be harmful, and even lead to death.
Earlier this week, the ABC reported on the unfortunate death of a bushwalker in Tasmania’s north western ranges. The coroner’s report said the most likely cause of death was an “exercise-related medical condition caused by drinking too much water during prolonged exertion.”
There you have it. Drinking kills. And finally, the anti-bottled water brigade have their health angle: all those fancy Evian and San Pellegrino labels are luring kids into the deadly habit of watering. Nicola Roxon, Tanya Plibersek, call your office!
This is only the latest piece of evidence that water, the warm and fuzzy name for dihydrogen monoxide, kills. Won’t somebody think of the children?
Prick With A Fork 
Water deaths on Kokoda – drinking too much water can kill you!
Link: http://annoyancesandirritations.blogspot.com.au/2010/06/why-did-four-kokoda-walkers-die.html
Great blog.
I think you will find that it is not so much “too much water” as not enough / insufficiently balanced electrolyte replenishment.
If the “packaged water” has been distilled or “demineralised”, your body will cheerfully continue passing out all those essential sodium and potassium salts. Without these salts, or in a case of serious imbalance, your nervous system starts to go to Hell.
“What about tank-water, you ask? I figure that in the days and places of this, people tended to eat a LOT more red meat, which contains some salts, and they certainly used a LOT more salt in their cooking. Water from the local creek, filtered through a canvas bag and “sterilised” by boiling is a pretty good bet, too.
Folk doing a lot of heavy work / trekking, etc. in hot places need to be VERY aware of this problem. There are commercially packaged electrolyte powders readily available and then there are the ludicrously expensive and nauseously coloured “lifestyle” drinks.