WATER SUPPLY, PLUMBING, ETC., FOR COUNTRY HOMES. 7 



Deep bored or driven wells are less liable to pollution than shallow 

 dug or bored wells, since in the first case the wells are usually im- 

 perviously cased and the surface water must filter through a depth 

 of soil equal to the depth of the well before gaining access to it, while 

 in the second case the wells are usually loosely lined with brick or 

 stone, and the surface water, having only a short distance to filter, 

 seeps in through the entire depth. 



That both deep and shallow wells are subject to contamination is 

 shown from many examinations which have been made. Of 177 deep 

 and 411 shallow farm wells examined in Indiana,^ 116 of the deep well 

 waters were of good quahty, 45 were bad, and 16 were doubtful; 159 

 of the shallow well waters were good, 209 were very bad, and 43 were 

 doubtful. 



The safety of water supplies when near sources of possible surface 

 pollution often depends largely on the character and quahty of the 

 material in which the 

 well is sunk. Surface 

 waters in sinking 

 through sandy soils or 

 surfaces are filtered, 

 and in the finer sands 



CSSS POOL 



Fig. 5. — Effect of pumping on ground water. 



much of the polluting 

 matter which they 

 carry is frequently re- 

 moved. In coarser 

 sands or gravel the 

 degree of filtration is 

 less, but water taken 

 from sands and gravels at a considerable depth may be considered 

 relatively safe. Waters from wells in clay are not often polluted, 

 since surface pollution filters through clay very slowly. 



Waters from wells in hmestone are frequently polluted, owing to the 

 fact that Hmestone soils usually contain passages and channels at 

 different depths which sometimes form a continuous passage for 

 underground water for a considerable distance and which are very 

 often directly connected with sinks and basins occurring here and 

 there on the surface. It is a common practice to dump manure, 

 trash, and garbage into such sinks or basins, and rain water faUing 

 into these plunges directly into the underground channels, carrying 

 with it the impurities from the basin to those points where wells are 

 sunk. In this manner garbage or refuse dumped anywhere in the 

 neighborhood of or even at a considerable distance from a well in 

 hmestone may pollute the water. Figure 6 shows how the pollution 

 of wells and springs may occur in Hmestone. 



1 Ann. Rpts. Ind. Bd. Health, 27 (1908), p. 345; 29 (1910), p. 349. 



