Until recently, city administrators and planners believed that the use of construction techniques involving surface trenching was the only option for the construction and repair of utility services. It was assumed that existing services were in good condition unless there was evidence to the contrary. In reality, gradual deterioration went unnoticed and failures occurred without warning, in many cases requiring an urgent response.

Over the last 25 years, it became apparent that little was known about existing utility services. Installation drawings, where they existed, gave little information on pipe capacity or materials used. Furthermore, the condition of the pipe linings was unknown, leakage and infiltration were unmeasured and related health issues were often not addressed.