Which tool is typically used to check the water flow rate?

The weir cup is designed to measure the flow rate of water by capturing a specific volume over a set time, allowing for precise calculations of flow rates in open channels. This tool works on the principle that water flowing over a weir will have a predictable flow rate that corresponds to the head or height of the water above the weir. It is especially useful in applications where a continuous flow rate needs to be measured, such as in drainage systems or environmental studies.

While other tools are valuable in plumbing, they serve different purposes. A flow meter directly measures water flow and is widely used in various systems. A pressure gauge is crucial in determining the pressure within a plumbing system, but it doesn't directly assess flow rate. A thermometer measures temperature, which, while important for maintaining the efficiency of hot water systems, does not provide any information about how quickly water is moving through the pipes. Thus, the weir cup is the specialized tool for this particular measurement of water flow rate.