Grayl VELCRO Backpacks

Do you need a water filter or water purifier? 

• Filters: Remove protozoa (Cryptosporidium, Giardia) and bacteria (E. coli, Salmonella)—main concerns in the U.S. and Canada. 
• Purifiers: Also combat viruses such as hepatitis A, rotavirus and norovirus.  

Types of water filters 

• Straw: Light and easy to use, but only works when you're at a water source. 
• Bottle: Lightweight, quick and affordable. Water volume is limited by bottle size. 
• Gravity: Easy to use, handles large quantities of water, and has a replaceable element.
• Pump: Precise, works in shallow water sources and has a replaceable filter but bulky and requires cleaning.
• Ultraviolet light: Fast, no filter to replace; requires batteries and prefiltering for cloudy water. 
• Squeeze: Compact and affordable; water quantity is limited by reservoir size. 
• Chemicals: Inexpensive, ultralight backup method; long wait time and don't taste great.