This document discusses natural sources of water and various methods to purify water, including filtration, boiling, chlorination, and distillation. Filtration removes solid particles but not microorganisms or dissolved substances. Boiling kills microorganisms but does not remove other impurities. Chlorination kills microorganisms and is used for large quantities of water but too much chlorine is unhealthy. Distillation produces pure water free of all impurities through the boiling and condensation process.