The management of small community or household water supplies remains problematic in many parts of the world because of the difficulty of disinfecting drinking water using locally available resources. In many regions it may not be possible to obtain enough firewood to boil water because of the effects of deforestation and land degradation, and it is often difficult to obtain chlorination agents for water disinfection in these regions. Although a number of techniques have been developed for the solar pasteurization of drinking water, the application of these techniques may be hindered by the availability of thermometers or other devices for measuring when water temperature reaches levels where pathogen die-off will occur. In the absence of water temperature measurements, boiling is the only unequivocal way of ensuring of drinking water safety.
The following notes describe the construction of a solar water boiler made with recycled wastes and other readily available materials that is able to disinfect small amounts of drinking water for household use. Depending on the local availability of materials, the unit described can be constructed within a few hours for a material cost of about $US 2 - $US 5.