Water is the source of life and you need lots of water when you're traveling. Especially if you are hiking, biking---or just walking in a place like Egypt. But the collective plastic water bottles that tourists throw in the garbage each day is an environmental catastrophe, especially in countries with no recycling. If you want to keep hydrated without killing the land we live on, carry a pump or use some purification tablets.
I hate carrying more than I have to, so the purification tablets are the usual solution. The iodine ones are cheap and available anywhere, but pretty nasty tasting. If you pay a bit more and get the Micropur ones, the water tastes good and it doesn't even turn pink. They come in a package of 30, enough for 30 liters. If you buy them from Amazon or Magellan's, you'll pay $10-$15. If you can find them where you're going, however, you'll often pay less. I got my last packet for $7 in Cusco, Peru. Then you can fill up whatever bottle you have on you with whatever water is around, let it sit for a while, and then you're good to go.
