Water purification products are often overlooked by western populations as we are used to having clean drinking water literally on tap. This often gives a false sense of security when we wander in to the great outdoors. Drinking water directly from a stream that looks clean when your water bottle is used up may not be a great idea as it could contain dangerous micro-organisms such as Giardia and Cryptosporidium. Luckily there are many good water purification systems on the market. SteriPEN UV water purification devices and travel water purification chemicals quickly treat water to neutralise any nasty micro-organisms. If your water is brackish and contains a lot of particulates then you are going to have to filter the water first, either through a pre-filter or simply through some fabric. Alternatively, you could carry a portable water filter that will do this for you and also sterilise the water in one go, providing instantaneous clean drinkable water.