To ensure a dry barrel hydrant is draining correctly after a test, one should...

To ensure a dry barrel hydrant is draining correctly after a test, feeling for suction through the nozzle is an effective method. This indicates that the hydrant is properly draining and that there is no residual water left in the barrel. Suction at the nozzle means that air is being drawn in, which is a sign that the water has fully exited the hydrant and that the draining mechanism is functioning as it should.

The other options, while related to maintenance and inspection, do not directly address the specific concern of ensuring that a dry barrel hydrant is fully drained. Inspecting for leaks around fittings may help diagnose other issues, but it does not confirm the draining process. Checking the hydrant's color coding provides information about the flow rate and pressure but is not relevant to the draining status. Observing the water level in the barrel may indicate whether water is present, but it does not allow for the assessment of air flow, which is a more definitive indicator of correct drainage.