How can you quickly determine if a dry-barrel hydrant is still draining before replacing the discharge outlet cap?

To quickly determine if a dry-barrel hydrant is still draining before replacing the discharge outlet cap, feeling for suction at the opening is an effective method. This approach relies on sensing any negative pressure or suction that might indicate the hydrant is still expelling water. When a dry-barrel hydrant is functioning properly, it should completely drain after use to prevent freezing in cold weather. If there is suction present, it implies that water is still in the barrel or not fully drained, raising the risk of damage or failure if the cap is replaced prematurely.

Using other methods, such as observing for continuous trickles or vibration in the stem, may offer some insights but are less reliable in determining whether water is still present inside the barrel. Observation of the water level in the window slit can provide some information, but again, it does not definitively indicate the draining status of the hydrant like the presence of suction does. Therefore, feeling for suction directly addresses the concern of ensuring that the hydrant has completely drained before capping, making it the most effective and immediate method for confirming drainage status.