26 



An example of danger from refuse of a more disgusting type 

 is shown in Figure 12. Located in the middle of a well-traveled 

 street, only a few inches above a gutter filled with paper and 

 refuse, a part of which is sure to enter whenever a heavy rain 

 occurs ; open to the rain which washes into it from the steps lead- 

 ing down to it such dirt from the street as is brought in by the 

 feet of the users; subject to the dipping of all sorts of more or 

 less dirty buckets and utensils; receiving the underground drain- 

 age and presumably more or less sewage from the buildings on the 

 slopes above; and containing in its bottom several inches of de- 

 caying paper and other refuse, this spring is on the whole one of 

 the worst and most dangerously located sources of drinking water 

 in the United States. 



Cesspool 



00 



FIG. 13. Diagram showing manner in which springs may be polluted by 

 subsurface drainage. 



In farming districts pollution by subsurface drainage from 

 buildings on the slopes above the springs is not very common, al- 

 though many springs are located back of barns, below hogpens 

 and outbuildings. The placing of buildings above springs in- 

 tended for use should always be avoided, even if the spring is 

 several hundred feet away from the proposed site. (See Fig. 13.) 



Protection of Sink Holes. It has already been pointed out 

 that much of the water in limestones, the springs of which are 

 frequently used for drinking and domestic purposes, enters the 

 rock through open sink holes, into which in some places manure 

 and other refuse has been dumped or sewage- drained. Figure 8 

 shows a small but continuous stream of sewage from a large 

 college building discharging into a sink from which it finds its 



