Approaches to sewer maintenance: a review

Sewer maintenance and rehabilitation strategies developed in a number of countries are reviewed. Comparisons are made between those approaches that focus on a predefined subset of strategic sewers and those that consider proactive maintenance of the whole system to address the wider consequences of failure such as customer satisfaction, social disruption and environmental damage. A number of diverse methods are described which can be used to optimise and prioritise proactive maintenance by analysing sewer performance, and lessons are drawn from maintenance strategies developed for other buried infrastructure assets. Limitations in existing sewer databases are discussed and new methods of obtaining sewer condition information are described. The paper concludes that to be cost effective, proactive maintenance involving inspection and repair must be focussed on those pipes which can be shown to have an early predisposition to failure.