202 CONSERVATION OF GROUND WATER 



of the Ohio River at Parkersburg, W. Va., and at Charlestown, 

 Ind., depend upon infiltration of water from that highly pol- 

 luted stream; tests have shown the pumped water at nearly all 

 times to be within safe limits as to bacterial content. 37 



The Public Health Service recommends that rural wells 

 be at least 50 feet from any possible source of pollution, 100 

 feet from seepage pits and barnyards, and 150 feet from cess- 

 pool sources of pollution, 38 but these limits and others recom- 

 mended by state agencies are largely empirical, because there 

 has been very little research as to the distance that bacteria 

 may travel through specific rock materials and live to endanger 

 public health. It is impossible at present to designate reliable 

 limits of safety for specific areas. As a result public health 

 may be endangered by existing methods of supply and dis- 

 posal in some places. In other places regulations based upon 

 squeamishness rather than scientific knowledge require dis- 

 posal systems that go far beyond an adequate protection of 

 public health and may involve unnecessary cost in money or 

 waste of water. 



The danger of bacterial pollution is likely to be greatest in 

 limestones and other very permeable materials. Recent out- 

 breaks of typhoid fever and gastroenteritis have resulted from 

 pollution of private and municipal water supplies in Fillmore 

 and Olmsted Counties, Minn. The pollution of these supplies 

 was traced to sinkholes and stone quarries through which 

 partly treated sewage and excreta were being introduced into 

 the limestone aquifer which yielded water to the supply 

 wells. 39 Many springs issuing from limestone discharge pol- 

 luted water in the Tennessee Valley, in the Ozarks, and other 

 limestone regions. Drainage and waste-disposal wells are likely 



37 Jeffords, R. M., Ground-water Conditions along the Ohio Valley at Parkers- 

 burg, West Virginia, W. Va. Geol. Survey Bull. 10, pp. 46-49, 1945. 



Kazmann, R. G., River Infiltration as a Source of Ground-water Supply, 

 Am. Soc. Civil Eng. Trans, vol. 113, pp. 411-412, 1948. 



38 "Joint Committee on Rural Water-supply Sanitation," U.S. Public Health 

 Serv. Supp. No. 185 to Public Health Rept., pp. 17-18, 1945. 



39 Kingston, S. P., Contamination of Water Supplies in Limestone Formation, 

 Am. Water Works Assoc. Jour., vol. 35, pp. 1450-1456, 1943. 



