The term 'water usage measurer' can be summarized as a job that requires the use of a METER. A METER is a device used to measure the amount of water used in a given area. It is typically used to monitor water usage and ensure that it is within acceptable limits. The METER is usually connected to a water supply system, such as a public water system or a private well, and records the amount of water used over a certain period of time. This data can then be used to determine how much water is being used and if it is within acceptable limits.