8 
BTJLLETIX 57, TJ. S. DEPARTMENT OF AGEICULTUEE. 
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 LOCATIOX AXD 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 permit, it is a good idea to provide 
impervious floors with 
water-tight drains for 
farm buildings and 
stock pens. 1 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 
manure, or rubbish should be 
Fig. 6. — Pollution of subsurface water in limestone 
but to save the manure. Xo garbage, 
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 some 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 AXD 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 kind of well used, and one should be acquainted with well 
JTJ.S. Dept. Agr., Farmers' Bui. 481. 
