* Fil­ters — The main advan­tage is they will remove all dirt, con­tain­ments, and organ­isms. How well the fil­ter works will depend to the phys­i­cal size of the pores in the fil­ter medium. If you have a fil­ter you should under­stand the level that you are fil­ter­ing to. Fil­ters are gen­er­ally heav­ier of the options. Dif­fer­ent fil­ters will have dif­fer­ent attrib­utes such as fil­ter rate, method (pump, grav­ity fed), etc. You should under­stand how to repair the fil­ter in the field.
* Chem­i­cal sys­tems – Gen­er­ally lighter and can kill most micro-organisms given appro­pri­ate time. Chem­i­cal sys­tems are affected by tem­per­a­ture. Chem­i­cal sys­tems will not remove dirt/debris or any other con­tain­ments. Each chem­i­cal sys­tem has lim­i­ta­tions and advan­tages. It’s worth­while to under­stand the pros/cons of each or at least your system.
* UV kills organ­isms by shoot­ing UV light into water given appro­pri­ate expo­sure time. With the steri-pen, you are lim­ited to 1 liter at a time. UV is sim­i­lar to chem­i­cal sys­tems in that they do not fil­ter dirt/debris or con­tain­ments. Its effec­tive­ness can be affected by the con­di­tion of the water (muddy may not be as effec­tive). For that rea­son, Steri-pen rec­om­mends use in clear water. Over longer peri­ods or fur­ther in the back­coun­try, it may be good to have a back-up in case your device fails.


Notes from per­sonal expe­ri­ence:
I mainly use Aqua Mira or boil­ing as I am usu­ally most inter­ested in an effec­tive solu­tion for the light­est weight. Some have com­plained of a slight after taste. I tend to use 5 drops per liter instead of the rec­om­mend 7 and I haven’t had any issues with taste. This is not rec­om­mended by the man­u­fac­turer so please con­sider your risk and make the best choice for you. If you are con­cerned about chlo­rine in the water, you may want to look at your local city water source as well.

Remember, a chem­i­cal solu­tion isn’t always the right choice. I eval­u­ate based on sev­eral fac­tors includ­ing: equip­ment avail­able, trip length, water sources, group size, tem­per­a­ture and weight. For exam­ple, what I would use in the Wash­ing­ton back­coun­try might be dif­fer­ent than a remote vil­lage waterhole.

Most water in the back­coun­try of Wash­ing­ton has min­i­mal debris and is rel­a­tively clean. Some would say it doesn’t even need treat­ment. I tend to take the more con­ser­v­a­tive approach and treat – espe­cially dur­ing sum­mer months. Many of our areas, espe­cially ones where aver­age hikers/backpackers/climbers go, are high-use areas. I know sev­eral peo­ple who have become ill from Gia­r­dia or Crypto or other water­borne organ­isms. What I can say is that the recov­ery process from these bugs can be exten­sive and most were suf­fi­ciently ill to regret not mit­i­gat­ing the risk. If you choose to not treat/filter, eval­u­ate the risk and make a con­science choice. I don’t treat 100% of the time, but I don’t take the deci­sion lightly. For cer­tain, you can never be sure. For exam­ple, one group I know decided to drink from a stream in a very low-use area, only to walk upstream and find a dead elk car­cass lay­ing in the water. Clean upper moun­tain water is a mat­ter of per­spec­tive. It depends on the moun­tain, your route, and time of year. For exam­ple, Mount Rainier sees around 1.7M peo­ple per year, with over ten thou­sand attempt­ing to climb it. That’s a lot of poop. At high alti­tude, I often use rodents as an indi­ca­tion of use. I’ve camped at 13,300’ on Mt Rainier in the sum­mer and there were still mice. There is only one rea­son for mice to be up at that ele­va­tion – people.

For some­one start­ing out, the best advice I could give is: learn the options and risks so you can make informed deci­sions and have flex­i­ble options. What works for one per­son or sit­u­a­tion may not work for another. Try not to attach to hard rules. No one solu­tion is per­fect for every sit­u­a­tion. In addi­tion to word of mouth, prod­uct infor­ma­tion and search­ing the web can be use­ful resources. Every­one will have dif­fer­ent expe­ri­ence and knowl­edge lev­els. Tri­an­gu­late from mul­ti­ple sources and then decide what’s best for what you need.

Have a good sys­tem you like you use? Leave a com­ment and share!

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