If to judge from the bulk of real time alerting technologies offered for the prevention of water losses, compared to simply none sewer leakage real time alerting technologies... the answer seems to be clear.
Are we are being leaded by a concept that loss of money due to leaking drinking water is not acceptable, but making profit from getting rid of alarming percentages of public paid collected wastewater into sub- soil is OK??
I have more trouble with water leaking into the system not out. I believe the general goal for most sewer systems is to clean every 24-30 months and have a camera inspection done every 5 years.
This plays into the misconception that sewage is a waste. Our digester produce methane gas that we use to recover power and heat. The sewer sludge is processed to reduce pathogens and vector attraction and used as fertilizer. Sewage leaks out and I produce less power. We are also looking for opportunities to re-use the water.
No doubt about the fact that I&I is a big problem for WWTP's operators in the same way that loses of wastewater, as a result of spillages and exfiltration from sewerage systems, is a big problem before all else for the environment.