Hydration systems are made up of a number of components for carrying and/or making water potable (drinkable). An earlier post ‘Water on the Trail‘ describes some background, here the focus is on available gear/options, in particular, filter systems. Typical filters will remove 99.99999% of all bacteria, for example salmonella, cholera, & E.coli and remove 99.9999% of all protozoa, for example giardia and cryptosporidium. Over time, filters will clog up with debris and sediment and need to be back-flushed or cleaned. Filters are usually small and lightweight, consider carrying a spare or alternative backup water purification method – like sterilization tablets.