What method should be employed to check the accuracy of a water flow meter?

The most effective method to check the accuracy of a water flow meter is by utilizing a stopwatch and a graduated cylinder. This approach allows for a hands-on measurement of water flow that can be directly compared to the readings from the flow meter.

To perform this check, you would collect a known volume of water using the graduated cylinder while timing how long it takes to fill it. By comparing the actual volume and the time taken to the flow rate indicated by the flow meter, discrepancies can be identified. This method is simple, requires basic equipment, and provides reliable results under various operational conditions.

While other options involve different types of measurements, they may not directly confirm the accuracy of the flow meter itself. For example, a flow gauge might measure flow rate but may not help verify the flow meter's reading under actual operating conditions. A digital meter serves a similar function to flow meters; therefore, it doesn't directly check the accuracy of a different meter. A pressure gauge primarily measures pressure, which although related to flow, does not directly assess the accuracy of the flow meter in question. Consequently, utilizing a stopwatch and graduated cylinder remains the best choice for checking accuracy.