490 



WATER SUPPLY AND SEWAGE DISPOSAL 



generally be true for cities obtaining their supply of water from 

 wells. How, then, is the city supply of water kept under 



FIG. 300. Plumbing in a modern city dwelling. 



pressure? One of two methods is generally followed. First, 

 in practically all city systems formerly, and in many small 

 city systems today, an elevated tank, generally called a STAND- 



