FARM SANITATION 



493 



Water Storage. The size of the storage tank and reser- 

 voir will depend primarily on the kind of power used for 

 pumping. It is customary to provide in storage a supply to 

 last five days when the pumping is done by a windmill; and 

 when a gasoline engine is used, the storage capacity may be 

 reduced to a two-days' supply. 



The two general methods 

 of storing water are by the use 

 of the elevated tank and the 

 pressure tank. The first of 

 these depends upon gravity to 

 force the flow of water, and the 

 second uses compressed air. 



Towers and Tanks. The 

 ideal location for an elevated 

 water reservoir is upon some 

 natural eminence. If the emi- 

 nence is high enough to justify 

 it, the reservoir may be built 

 beneath the surface like a cis- 

 tern, thus insuring that the 

 water will be kept cool. If 

 there is no natural means of 

 securing elevation, the tank 

 must be placed upon a tower 

 or in a building. The height 



of the tower will depend upon the height of the buildings to 

 which the water is to be delivered and upon the pressure 

 desired. The tower may be made of steel, wood, or masonry. 

 Masonry tanks are best, but often the cost is prohibitive. 



A tank on a tower is exposed more or less to the weather 

 and will give trouble from freezing. This is especially true of 

 steel tanks. Wooden tanks are preferred over steel for out- 



Fig'. 304. An Iowa silo with a 

 masonry water supply tank on 

 top. 



