Which method is least effective when dealing with low water pressure?

Ignoring the symptoms of low water pressure is indeed the least effective method for addressing the issue. By choosing to overlook the signs of low pressure, one fails to identify the underlying causes that could range from leaks in the system to blockages or issues with the water source itself. This passive approach prevents any proactive measures from being taken, which can lead to continued problems and possibly more extensive damage or costly repairs in the future.

In contrast, conducting pressure tests, repairing visible leaks, and using flow rate meters are all proactive strategies aimed at diagnosing and resolving the issue. Pressure tests can pinpoint specific faults in the system, repairing leaks directly addresses one common cause, and flow rate meters help in understanding the system's performance, allowing for a more informed diagnosis. Each of these methods contributes positively toward resolving low water pressure and maintaining an efficient water system.