Only water from developed systems at recreation sites is maintained safe to drink. Open water sources are easily contaminated by human or animal waste. Treat water from springs, lakes, ponds, and streams before drinking. One recommended treatment is to bring clear water to a rolling boil for five minutes.
A special concern to backcountry visitors is the presence of the microscopic organism Giardia lamblia in many of the area’s waters. Giardia is spread primarily by fecal contamination of water sources by infected mammals (including humans). Giardia may be contracted by drinking untreated water. Symptoms may recur for years after infection and include diarrhea, gas, loss of appetite, abdominal cramps, and bloating. These symptoms may appear within a few days to a few weeks after infection. If you develop these symptoms, contact your doctor and be sure to mention that you were in an area where giardia may have been present.