This document discusses various sources and characteristics of water. It describes rainwater, surface water sources like reservoirs and rivers, and groundwater sources like shallow wells, deep wells, and springs. Key points are that rainwater is the purest source but availability depends on rainfall. Surface water is prone to contamination while groundwater generally requires less treatment but can have high mineral content. Wells tap either shallow or deep groundwater and are classified by construction method. Sanitary wells constructed with proper lining, drainage, and hand pumps can provide safe drinking water.