8 



BULLETIN 57, U. S. DEPAETMENT OF AGEICULTUBE. 



Deep wells in granite or jointed rock are often polluted, although 

 cased to a great depth, since polluted water may sink in a zigzag 

 course along the rock joints until it reaches the bottom of the well 

 casing. It is therefore necessary to exercise care in the location of 

 the well and in the preliminary protection from pollution, 



WELL LOCATION AND PRELIMINARY PROTECTION. 



The farm well, especially a shallow dug well, should be located 

 somewhat above the barns, buildings, yards, and stock pens, or at 

 least in such a position that the surface drainage from all possible 

 sources of animal and vegetable contamination is away from the well. 

 The location should also be as far removed from these sources as 

 convenience will permit. 



To properly safeguard wells against outside contamination, first, 

 all sources of contamination should be removed as far as possible. 

 If local conditions and prices will j^ermit, it is a good idea to provide 



impervious floors with 

 water-tight drains for 

 farm buildings and 

 stock pens.^ Under 

 the same conditions 

 concrete manure pits 

 might well be pro- 

 vided to not only pre- 

 vent the liquid ma- 

 nure from polluting 

 the neighboring soil 

 but to save the manure. No garbage, manure, or rubbish should be 

 dumped into sinks or basins in the immediate neighborhood, and these 

 should be fenced off and kept free from polluting matter. The house 

 should be provided with som.e safe method of sewage disposal, while 

 slops and garbage from the kitchen should be deposited in tightly cov- 

 ered garbage cans and disposed of by burying in the fields, burning, or 

 feeding to pigs. The use of privy vaults and leaching or overflowing 

 cesspools should be absolutely avoided, since they are likely to be 

 sources of the worst contamination. Second, the farmer should be- 

 come acquainted with the various types of wells and the best methods 

 of protection, and the well should be so protected as to exclude filth 

 from those sources of contamination which it has been impossible to 

 remove or have been overlooked. 



TYPES OF WELLS AND METHODS OF SINKING. 



In the selection, location, and sinking of a well it is always a good 

 idea to consider permanence in addition to safety. This will depend 

 on the kuid of well used, and one should be acquainted with well 



Fig. 6.— Pollution of subsurface water In limestone. 



1 U. S. Dept. Agr., Farmers' Bui. 481. 



