54 Our Surroundings 



pools or other places where organic wastes are liable to accumulate. 

 This is especially important if the waste comes from the human 

 body, since it may contain disease germs. Cases of typhoid fever 

 are often traced to water taken from a well near which such 

 waste is allowed to remain. Such material in water is called 

 pollution. Since ordinary wells receive their supply from water 

 purified by soaking or filtering for some distance through the 

 ground, they should be so constructed that surface water cannot 

 get into them directly. 



Sanitary Control of Sources of Water. Not only is it 

 necessary to protect wells from pollution, but it is also necessary 

 to protect all sources of water supply such as springs, rivers and 

 lakes. If cities on river banks could prevent the disposal of sew- 

 age into the river by cities and other communities located farther 

 up the stream or on the banks of its tributaries, there would not 

 be the necessity for expensive water systems. Such sanitary con- 

 trol is very desirable. 



It often happens that persons returning from a vacation spent 

 at a summer resort or camp are taken ill with typhoid fever or 

 some other ailment, the germs of which were acquired from the 

 water in the places where they were staying. This danger can 

 be avoided only by proper sanitary control of the sources of 

 water supply. 



City Water Supply. In cities and towns of large size, the 

 problem of securing an adequate supply of pure water is often 

 a difficult one to solve. Although many cities are near rivers and 

 lakes where there is plenty of water, it is often not fit to drink 

 owing to sewage material which has been thrown into it. On this 

 account it has become necessary either to bring water from great 

 distances, or to install large water systems with settling tanks and 

 sand filters to purify the water, and extensive pumping apparatus 

 to force it to the places where it is to be used. 



In order to get sufficient pure water for her millions of in- 

 habitants, New York City bought a great area in the Catskill 

 mountains and compelled the people living there to move away so 

 that they could not pollute the water in the streams and reservoirs. 

 This Catskill region is over 100 miles from New York City. 



