According to national standards, water utilities have to guarantee the supply of water to their consumers in appropriate quality, quantity and pressure. Therefore, foresighted rehabilitation planning is necessary. In some cases the buried water supply system is more than 100 years old but still in use. The aging process of the material derived from failures can be noticed by the water utilities in the daily operation, where several factors influence the lifetime expectancy. It is nearly impossible to predict the first failure, but if a failure occurs caused by aging processes, the following failure can be described statistically. The decisions whether a pipe-section should stay in use and be repaired locally or be replaced can be supported by statistical analyses.

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