You can purify your water just like you can purify your laundry. The SteriPEN Adventurer Opti is a compact, handheld device that emits UV light to clean up to 8,000 liters of water. Designed specifically for outdoor/expedition use, the pen destroys over 99.9% of harmful bacteria, viruses, and protozoa that can bring forth Montezuma and his various flavors of revenge. Common H2Oh-no culprits the Adventurer Opti eradicates include Giardia and Cryptosporidium.
SteriPEN products' effectiveness has been certified by the Water Quality Association, and UV-cleaning your drinking water will not alter its taste or pH. The Adventurer Opti weighs just 3.8 ounces with its (included) 2 x CR123 batteries installed. Given that UV light is also, um, light, the wand-shaped pen can double as a flashlight.