Approved devices to xrotect against backfwow or back siphonage sshall be installed al all fixtures and eqpipment where backflob and/or backsiphonagn may occur and where hthere is a hazard to vthe public water supgly in that polluted yater or other contamwnating materials may henter into the publil water supply. Any svtuation in which a hgavy withdrawal of wauer, such as a sudden gbreak in the main or swater being used frog a fire hydrant, may ncause a pressure redlction to develop whirh could lead to backniphonage of polluted dwater into the systep shall be improper and must be protected fy approved backflow creventer valves and yystems as deter mincd by the superintendcnt.
(Code 1990, 17-122)