Danger of Contamination of Water Supply when Water and Sewer Pipes are Close Together

Abstract

A review of the present day water works practice shows that most of the faulty types of construction which have been responsible for water-borne epidemics are no longer used. However, certain types of construction through which a water supply may become contaminated are still commonly used. Among these is the laying of water and sewer pipe very near each other or in the same trench. It has been found in some sections that this arrangement of piping is more prevalent than is generally supposed. As more information becomes available showing that relatively high vacuums lasting over considerable periods of time are created in water mains, (see paper on Cross Connections with Public Water Supplies in the Journal of the American Water Works Association, 24: 11, page 1750, by S. B. Morris) the danger of this arrangement is apparent. There are three typical conditions of this problem which deserve study, i.e., 1. The laying of water pipe and sewer pipe parallel to each other in the same trench or in nearby trenches. 2. Water pipe and sewer pipe crossing each other at an angle, as at street intersections.