Sewer Pipeline Performance Indicators: Learning from the European Experience

The United States (U.S.) has the most extensive wastewater infrastructure system in the world. Approximately 147 million people are served by about 19,000 municipal sanitary wastewater collection systems representing about 500,000 sewer miles (not including privately owned service laterals connecting buildings to sewer mains). The operation and maintenance (O&M) and renewal activities required to support this infrastructure represent a major capital investment. The Congressional Budget Office (CBO) estimated that the total public spending on sanitary wastewater infrastructure was approximately $22 billion in 1994 alone. This represents 13 percent of total infrastructure spending in the U.S. Historically, U.S. public works managers have generally rehabilitated a component of a sewer system only after it had failed due to a break, leak or stoppage. System failures often resulted in releases of untreated wastewater to the environment and service interruptions for customers. Despite the high costs and the key role that wastewater collection systems play in servicing the public and protecting the environment, a study by the National Research Council found that few or no standards exist for evaluating their performance. In more recent years, public works managers have shifted to a more comprehensive and proactive approach to infrastructure asset management. In this framework, managers attempt to identify rehabilitation needs before they result in breaks in service or releases to the environment.