Polluted Water Can Ml You 223 



persons who are faced with seasonal water shortages find it ex- 

 pedient, even if expensive, to drill a well and insure themselves of 

 an abundant year-round supply of potable water. 



SPRINGS 

 There are few sights more refreshing to a hot, tired person than 

 cool water flowing from a spring in a shady glen on a warm sum- 

 mer day, but opinions vary as to the safety of such water for human 

 consumption. Spring water is an underground supply that finds 

 its way to the surface of the ground. Theoretically, the filtration 

 this water has undergone should make it potable, but unless the 

 sanitary conditions around the outlet of a spring are known, 

 pollution is always a possibility. Surface pollution from man or 

 animal wastes must never be minimized. Should there be any 

 doubt about the potability, there are simple ways of treating water 

 to make it safe for drinking. A few of these technics will be dis- 

 cussed later in this chapter. 



CISTERNS 

 In some sections of the United States a cistern is an important 

 means of providing soft water for residents of the community. 

 Where rainfall is limited, or when chemical elements in the soil 

 tend to make water "hard," it is customary to gather rainwater from 

 the roofs of the houses and to collect it in storage tanks after a 

 preliminary filtration to remove visible dirt and at least part of the 

 trapped organisms. 



RESERVOIRS 



Cities and municipalities are faced with the challenge of supply- 

 ing an adequate water supply to the inhabitants at a reasonable 

 price, and the reservoir is a common means of storage. The 

 water is collected in open areas, usually behind a dam in a process 

 called impounding. As the name reservoir indicates, the collecting 

 area provides a reserve supply to be drawn upon as needed. 



Any attempt to cover these huge areas to prevent outside 

 contamination is impractical. While it is true that upon standing, 

 water tends to improve itself from bacteriological standpoints, some 



