Sewer network measurements should be performed at key moments to ensure proper infrastructure operation and regulatory compliance: When commissioning a new network or facility (e.g., treatment plant, sewer network). After rehabilitation or modernization work to verify effectiveness. As part of periodic diagnostics or audits to identify potential issues (e.g., inflow and infiltration, leaks, overloads). When problems are identified, such as overflows, leaks, or anomalies in wastewater flows. These measurements help prevent environmental and financial risks while meeting legal obligations imposed by water regulations or water authorities.