TABLE OF CONTENTS Thomas M.Walski
Pennsylvania American Water Co
Wilkes-Barre, PA
James W.Male
Department of Civil Engineering
University of Portland
Portland, OR
When compared with other infrastructure networks, water distribution systems are extremely reliable. It is not uncommon for pipes to perform for more than 100 years without a break or a leak. Numerous pumps have run for over 40 years with only minimal routine maintenance. In fact, in some older cities, wooden mains still convey water. As is the case with systems that require little attention, especially one that is not visible, water distribution systems are usually taken for granted. However, good maintenance practices can extend the life of distribution system components and rehabilitation can further prolong their life.
Many water systems are old yet perform adequately. However, a number of factors at work might lead to failure if left unchecked. Some of the primary factors are described below.
Most moving components will wear out over time. Distribution systems have few moving parts and thus are not extremely susceptible to wear. Pumps are the components most likely to face wear problems. Depending on the type of pump, routine maintenance can maximize the life and maintain the efficiency of pumps. The moving parts in control valves also need frequent routine maintenance to continue functioning adequately.
Many distribution system components are made of metal, and, on contact with an electrolyte, metal tends to corrode. Metal pipes and tanks are the most obvious example...
