With so many individuals concentrated in limited areas on the mountain it is vital to protect water sources from contamination. We purify all drinking water by boiling it. You may feel more comfortable using purification tablets. Never use soap directly in water sources. Even the best biodegradable soaps take several days under ideal conditions to break down. Where possible move at least 10 meters away from the water sources before using soap. Human faecal material is a major source of water contamination on the mountain. Where they exist, use an established toilet (choo). Ultraviolet radiation from the sun and organisms present in the soil are the best decomposers of human waste. At high altitudes those soil organisms are not very abundant. Therefore, sunlight provides the best form of decomposition. Select a site well away from campsites, trails and at least 30 meters’ away from water, with lots of sunlight exposure. Leave faeces on the surface of the ground. Scattering and smearing the faeces around will maximise exposure to sunlight. At lower elevations such as below 3500 meters’ where soils are rich in decomposing organisms, burying faeces in shallow holes is the most effective method. Toilet paper and sanitary towels should be packed out with other litter.