What contributes to non-revenue water in wastewater systems?

Non-revenue water in wastewater systems refers to water that has been produced but is not billed to customers. This can occur due to several factors, which is why the second choice is the correct one.

Leaks in the system contribute significantly to non-revenue water as these are instances where treated water escapes due to failures in pipes or infrastructure, leading to water loss before it can even reach customers. Unauthorized use involves instances where individuals use wastewater services without proper permission or are not accounted for in billing, thus contributing to lost revenue. Metering errors occur when the measuring devices used to track water usage are faulty, resulting in inaccurate billing, which also affects overall revenue.

The other options do not fully encapsulate the range of factors contributing to non-revenue water. Authorized use and regular maintenance operations typically help improve efficiency and accountability in wastewater systems, while excess treatment capacity may not directly translate to water loss or lack of revenue generation.