A water supply test for a sprinkler system should be performed at which of the following locations?

Performing a water supply test for a sprinkler system at the water meter is critical because it provides an accurate representation of the available water supply before it enters the building's plumbing system. The water meter is where the municipal water supply connects to the private plumbing system, and testing at this location allows for measurement of the flow and pressure that will be available to the sprinkler system.

This approach ensures that any potential pressure losses or flow restrictions that might occur within the building's internal piping do not affect the test results. It provides a baseline for the water supply's capacity, ensuring that the sprinkler system can operate effectively during a fire emergency.

Testing at locations like the nearest fire hydrant, the main sprinkler valve, or the pump house may yield different results due to various factors like pipe sizes, bends, or additional fittings that could affect flow and pressure. Thus, the water meter serves as the most reliable point for determining the appropriate water supply conditions for the sprinkler system design and function.