Read the excerpt from "Water Efficiency Strategies."

Accounting for water is an essential step toward ensuring that a water utility is sustainable. This is best accomplished when water systems meter use by their customers. Metering helps to identify losses due to leakage and also provides the foundation on which to build an equitable rate structure to ensure adequate revenue to operate the system.

What does the phrase "accounting for water" mean?

finding leaky water pipes

fixing faulty water meters

testing water clarity

measuring water usage