Reddit mentions of LIFESAVER Water Filtration Filter Bottle Purifier kit for Camping Emergency prep Backpacking Hiking Outdoor System Travel Virus Bacteria & Cyst Removal Bottle 4000UF

Most people can't fit enough water in their flats (especially for us urban dwellers) so I recommend getting some kind of water filtration system. Even a simple Lifesaver bottle can produce enough clean water for a family to get through a couple of weeks with no utilities.

I never thought I would seriously contemplate buying a $150 water bottle.

http://www.amazon.com/Lifesaver-Bottle-4000-Ultra-Filtration/dp/B001EHF99A/ref=sr_1_1?ie=UTF8&qid=1342068535&sr=8-1&keywords=lifesaver+bottle

There are two kinds of problem.

The high end solution, like the LifeSaver, can work with surface water.

If you're dealing with public water that's been processed by the local government's water treatment plants (which might not be to the standard your body is used to), then a filter bottle might be the right solution. If it's a biologic contaminant, then something like a SteriPen could be the right answer.

by "the market" do you mean "available for purchase by anyone?" if so, it is.

Amazon.ca

This is also just over $100, but it is awesome for camping. Never worry about your water again.

This is a slightly cheaper, more physical way to purify water in the woods.

EDIT: Filters kind of ruin the BIFL philosophy, unless you're looking at the possibility of it saving your life in woods.

That's what I was thinking. Steripen it first to kill everything then squeeze it through something like sawyer.

I was looking at the LifeSaver bottle system here: https://www.amazon.com/gp/product/B001EHF99A/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

Which seems to be an all in one. But, the temperature ratings a problem for freezing.

I expect I've made some glaring oversight here, but would it be possible for me to jerry rig something like this filter in between the greywater and fresh water tanks? It seems to me that would be a very simple solution to the problem, though I'm sure there must be some reason people don't use it... Of course the cost per litre is very high, and that may be the only reason it's not used?

I've researched and tested and researched some more, filter bottles for my upcoming trip through SE Asia. Bottom line, probably more hassle than just being careful and sticking to bottled water. Those two you linked are not going to do anything for bacteria and viruses. Viruses will be the main concern when traveling and drinking water but is also the hardest to filter since the filter has to be around 25nm and below for that. Basically if you are really worried and really want a cheap solution you can try the Sawyer Water Bottle, it doesn't filter viruses but it looks to be the easiest and non-messy. I tried the Lifesaver Bottle but it ended up leaking all over the place and being very bulky.

Impressionnant ! Mais 170 € la bouteille...