168 UNIVERSITY OF WISCONSIN STUDIES 



9) The location of wells, pumping apparatus, exposed 

 suction mains, reservoirs and filters where they will be subject 

 to flooding with surface water. 



10) The improper construction of well casings and covers, 

 and the lack of adequate provision for surface drainage to 

 prevent pollution of the well with surface water. 



11) The construction of pits around wells at the surface 

 in which all or a part of the pumping equipment is located. 

 This applies especially to drilled wells. It is difficult to pre- 

 vent surface and waste water from collecting in such pits. 



12) The connection of any part of the system with sewers 

 which makes it possible for sewage to back up into wells, well 

 pits, storage reservoirs, etc. 



13) The improper construction of underground and sur- 

 face reservoirs. This includes structures that are not water- 

 tight, those where the covers admit surface water and others 

 where the clean-outs are connected with sewers or bodies of 

 polluted water, the surface of which may be raised to an eleva- 

 tion higher than the bottom of the reservoir. 



14) The installation of emergency connections which may 

 permit untreated surface water, or water of unknown or ques- 

 tionable sanitary quality, to be admitted to the system. There 

 should be a complete physical separation between water sup- 

 plies that are safe and those that are known to be unsafe from 

 a sanitary point of view. 



Many of these defects have been the cause of epidemics of 

 water-borne diseases, consequently, their sanitary significance 

 is at once apparent. These errors can be prevented in new 

 supplies and corrected in existing supplies by proper health 

 administration carried out by trained workers who have the 

 proper facilities to put such supervision into effect. 



CONCLUSION 



The purpose of this article is to draw the attention of 

 health authorities and others to the importance of thorough 

 investigation work when the safety of a water supply is to be 

 determined from a sanitary point of view. The investigation 

 should be undertaken by trained workers who understand the 



