Comparison of the behaviour of ultrasonic, single- and multi-jet water meters during intermittent water supply

<p dir="ltr">Water meters are essential tools for managing water distribution systems, helping define terms for financial and mass balances, and clearly separating revenue from non-revenue water. In a system where the supply is intermittent, meaning it is not available twenty-four hours a day, seven days a week, even the basic operation of water meters can be at risk. During system filling, the air in the pipes is pushed forward by the water and flows through leaks and user connections, where valves are typically open to refill private tanks. The airflow's effect on the accuracy and reliability of water meters at user connections can lead to overreading, causing users to be charged for air instead of water consumption. Additionally, water meter turbines can be severely damaged by the high rotation speeds caused by air in dry conditions. In this paper, ultrasonic water meters are tested as an alternative to single- and multi-jet flow meters in the Water Engineering Laboratory at the University of Perugia, Italy, under various operating conditions. As expected, ultrasonic water meters are unaffected by airflow and can be used even when the system involves intermittent water supply.</p><p dir="ltr">This paper was presented at the 21st Computing and Control in the Water Industry Conference (CCWI 2025) at the University of Sheffield (1st - 3rd September 2025).</p>