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Other Publications Year : 2004

Water pipe maintenance: repairing or renewing

Maintenance des conduites d'eau potable : faut-il réparer ou renouveler ?


The fourth of the French water distribution network is estimated as being more than 60 years old. Therefore, many rehabilitation or renewal works seem to be necessary in the next future to keep this infrastructure in a good estate. Up to now, renewal decisions are often taken with regard to the failure rate and in relation with the road works planning. The present decision process is essentially curative; there is no planning of the needed budgets and of the renewal works. The aim of our work is to think out a decision tool helping to propose a sustainable budget evolution, for there are no subsidies given for renewal works. Besides, it will also give guidance for choosing the pipe or bundle of pipes to be renewed, taking into account the geographic area, works on other networks or on roads. The first step of the process is to evaluate the budgets that would be economically optimal taking into consideration the ageing process but also other technical, social or economical factors. This phase will give an irregular progression of budget needs with peaks that are not really sustainable for water utilities. However this step is necessary to have an idea of the estate of the network, to identify the most risky pipes and give an idea of the budgets to put in place. The next step, the real budgeting step, will take into account constraints such as limited budget and will try to propose a smooth and regular evolution of the budget needed for renewal for several years. The optimisation model will be presented in the paper. It uses a dynamic programming approach in order to decide when it is cheaper to renew than to wait for renewing and keep in place the old pipe and so accept the risk of failures given by the expected cost of maintenance. The dynamic programming approach allows taking advantage on the information profit given by each state of the decision tree. Our model uses the probabilities of failures given by survival models based on the pipe characteristics and its local environment and on failure history. The different costs try to show the effect of a failure on the consumption point through a hydraulic simulation, the sensibility of the different consumers facing a water delivery interruption, the connection with the environment of the pipe. The cost of maintenance includes the direct costs of reparation and social costs due to the social effects of the failure (water loss, damages, and interruption in industrial activity).The stress is put on interruption in industrial or trading activity. Simulations on a district of the town of Strasbourg will be presented. This approach takes into account technical and economical points of view and will lead to the working out of a decision tool for budgeting renewal expenditures and renewal works.


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Dates and versions

hal-02587616 , version 1 (15-05-2020)



C. Werey. Water pipe maintenance: repairing or renewing. Options values for energy issues, 2004, pp.161-177. ⟨hal-02587616⟩
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