After breathable air, water is the next vital need people have. Water is necessary for drinking and food preparation (2-5 L/day), personal hygiene (2-6 L/day), and cooking (3-10 L/day). Potable water is required to lessen the chance of spreading water-borne diseases and to have a functioning health care facility.1,2
Even if water is available, a loss of water pressure or of electricity for the pumps can mean that toilets become inoperable. Wastewater can be used to "prime" the toilets, but a plan for disposing of waste is necessary.
If large alternative water sources can be identified, a method of transporting the water must also be found. For smaller, more immediate needs, sterile saline and sterile water may be used, in emergencies, for hand washing, although it may be better to save the sterile water for drinking and cooking. Using waterless hand wipes conserves water.
Supplying sufficient amounts of clean drinking water is vital to prevent outbreaks of severe gastrointestinal disease. Nearly all springs, streams, and rivers are contaminated to varying degrees by commercial effluent, natural mineral run-off, or animal feces. Wells usually are not contaminated with microorganisms, but the water frequently has a high mineral content.
It seems logical to collect drinking water from atmospheric sources (rain, snow), but such water is often contaminated with dissolved and suspended substances. Even so, if properly collected, this water is within acceptable limits for potability. Using scrapings from the top layer of newly fallen snow is the best option. Less acceptable is collecting rainwater from a roof very shortly after a rain, using clean drain pipes. This method cannot, however, be used for snow, since it becomes contaminated prior to melting.
Improve the collected water's quality by filtering it through commercial filters or through white cotton cloth that has been boiled in soapy water and then rinsed thoroughly. Using that filter with new-fallen ground snow taken from the surface eliminates bacteria. Unfiltered ground snow has 44 bacteria/mL and cotton-cloth-filtered rainwater has 124 bacteria/mL. Unfiltered rainwater contains more than 1000 bacteria/mL with clumps of potentially pathogenic organisms. Filtering through filter paper, newspaper, four-layered gauze, and cotton is unsatisfactory.3 Bangladeshi villagers used old cotton saris to filter homemade drinks. They folded the sari cloth (mesh size ~20 micrometers) so it had eight layers. Filtering through this cloth reduced the cholera incidence by 48%.4
When using dirty or cloudy water, clarify it before disinfecting it. Filter it through a cloth or sand filter, or allow it to stand so that particles and associated bacteria sink to the bottom.
Disinfect the water, if necessary. Boiling or heating can be effective for small amounts (as for households). Heat water to temperatures >70°C (160°F) for 30 minutes to kill all enteric pathogens. If the water temperature ...