Alastair Sawday's 
Earthscan's 
Lonely Planet's 
Taking plastic bottles on holiday
The rubbish caused by plastic water bottles is bad enough at home, but the problem is a thousand times worse in countries where there may be no waste management or recycling facilities to deal with piles of garbage. Yet forgo buying bottled water and you risk illness from drinking unsafe local water...
If you're staying in a place where there will be a safe water source, such as a bulk water dispenser in the hotel, it's much better to pack a reusable water bottle that you can refill rather than buy bottles of water that you'll dump when you're done. Collapsible plastic pouches are easy to pack, while sturdy aluminium bottles with canvas coats keep the water cool and can be re-used for years.
Responsible travel companies that run trips to Africa and Asia, such as Exodus, KE Adventure and Dragoman, advise clients against buying bottled water and instead provide their own supplies of filtered/boiled water.
There may also be local clean water sources that you can use to top up your supplies en route. Treks organised by Himalayan Kingdoms along the Annapurna Circuit in Nepal stop off at community-run ‘safe water drinking stations’, which sell ozonated water at around 40p a litre and help support local economies.
A version of this article, by Richard Hammond, was first published in the Guardian.
water purification pills
The way to go are water purification pills... every traveller is recommended to carry their own water bottles and purification tablets.. and of course, in areas like the Annapurna trek in Nepal, ozonated purified water is available for about 4 bucks a bottle...
Iodine pills are good, though have a strange taste that takes getting used to. A neutralizer or a few pinches of concentrate helps.
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if you are not living on the edge, you are taking too much space...
http://www.socialtreks.com
water bottles or not??
Obviously it's incredibly important to keep hydrated when travelling, and we all know we should drink 2 litres of water a day, but this contributes to the vast amount of bottles that are thrown away every with little hope of being recycled.
We advise our customers to invest in a water purification bottle, which cleanses suspect water with an integral filter; there are lots of reputable brands on the market, although we favour the Swiss made Katadyn, as it is the lightest. You can then refill the bottle from the tap and drink safe in the knowledge that it filters out 99.9999% of water-borne bacteria and 99.99% of water-borne viruses.
My mum travels to Kenya, Uganda and Nepal frequently and she swears by hers; hope this helps!
Iodine and Chlorine pills
Iodine and Chlorine pills are fine, but they are not effective at removing pathogens such as Cryptosporidium or Giardia which are pretty much immune to such chemicals. In addition these chemicals do not remove dirt or sediment from the water so if the water is bad tasting to begin with then the pills will not improve that.
The only sure fire ways to clean water on the go is either boiling (a good rolling boil for 1 minute to ensure you kill the nasties - but still doesn't improve the taste) or a purification bottle which is by far the best option.
I would certainly opt for the bottle as mentioned previous - preferably one with a built in disinfectant. I can't comment on the others mentioned but would certainly recommend the Aquapure Traveller which handles not only the viruses, bacteria and pathogens to make the water safe, but also removes the particles, heavy metals and even chemicals found in the water so it tastes great too.
And to be green I'm not leaving 1000's of plastic bottles around the countryside either!
www.aquapuretraveller.com
www.bwtechnologies.com/iqs/sid.0353095079872130203753/aquapure_traveller.html