When we’re in the back country on backpacking and canoeing trips we have to purify our water. I see providing safe drinking water as a group rather than an individual responsibility. It is also something that needs to be simple, as foolproof as possible and reasonably affordable. I have tried several different filters and chemical treatments; all have had some significant drawbacks. Chemical treatment requires careful measurement, timing the treatment and often results in a noticeable aftertaste. Pump-type filters are prone to mechanical problems, need continual maintenance, are comparatively expensive, have complicated operating procedures and are slow in providing water for a large group of people. Pump type filters also need to be used at the water’s edge or require some sort of intermediate container to hold water. We’ve been using the Katadyn Base Camp filter for the past several years and have found it to be simple and reliable. We carry one for every nine or ten people on backpacking and canoeing trips. Gravity fed filters need no pumping. Simply fill the waterproof nylon reservoir with untreated water, hang it up and begin filling. Katadyn advertises that the filter delivers “up to 2.5 gallons of treated water in just 15 minutes”. Naturally as the filter ages the flow rate will reduce somewhat. A clip on the tubing acts as a spigot to control water flow. The glasfiber filter elements are easy to replace and fairly inexpensive ($40.00 or so at this writing). We carry a spare filter element on weekend trips, and two spare elements on longer outings. It is important to prime the filter by allowing it to fill with water before using. We have also had instances when the filter seems to get air locked, but gentle pressure on the filled bag will aid in priming. If the untreated water has a fair amount of visible undissolved solids we use a collapsible bucket to allow the solids to settle before putting it in the filter. The filter weighs 22 ounces. At around $70.00 the Base Camp is relatively inexpensive in comparison to pump-type filters. Even with replacing filters fairly often the price per person is very reasonable ($3.00-$4.00 per trip). More importantly the Base Camp Water Filter is easy to operate for even our youngest Scouts.