Impacts of the ageing and rehabilitation of water pipes on residence times at the residential neighborhood scale

The impact of ageing and rehabilitation on water residence times was evaluated in a looped drinking water distribution network, using hydraulic modeling and flow characterization. A reference scenario representing the best state of knowledge of the studied area was created and realistic scenarios were applied to evaluate the impact of ageing and rehabilitation of water pipes on residence times.Results showed that the ageing of infrastructures, with consideration for pipe corrosion and a 20% leakage loss increase, lead to an overall 10% water residence time reduction. Considering a non-uniform ageing of water pipes results in localized impacts brought by changes in hydraulic patterns. Considering pipe rehabilitation scenarios coupled with a 20% flow reduction leads to small water residence time increases (2--8 h), with the local pipe rehabilitation having the least impact on water residence times.