Preventing Hydrant Valve Damage
© 2001 Capt. Willis Lamm, Water Supply Officer, Moraga-Orinda (CA) Fire District

A construction or fire crew is shutting down a fire hydrant but the water doesn't stop flowing. Typically their first reaction is to crank down harder on the spanner. After all, the valve must not have closed all the way.

Oftentimes the reason the valve may not have closed is due to the fact that some kind of debris is stuck in the valve. Forcing the valve closed on a hard object will likely only result in damaging the valve seal, or worse, damaging the valve seat and bending the stem.

All sorts of debris may be present in water mains including broken off pieces of scale, gravel, and tools or construction materials that juveniles enjoy tossing into open pipes during construction projects. Getting these materials out of the system is one important reason for hydrant testing, however not all materials blow clear of hydrants during in-service tests and they could appear any time the hydrant is flowed at high volume.

This valve was cut out of a new hydrant.
Someone tried to force the valve closed on a piece of rebar that was in the main

  SAFE SHUT DOWNS

We worry about water damage from flowing hydrants but fighting a valve that won't shut down will usually not help stem the flow of water and wastes valuable time. If a hydrant fails to shut down properly here are some options to try in lieu of damaging the valve.
  • Reopen the hydrant fully and try to discharge the stuck object, then reclose

  • Replace the hydrant cap if the flow isn't too great to do so.

  • Shut down the hydrant street valve if accessible.

  • Attach a gate valve and shut the valve. (Fire crews could use a 2½" nozzle with the tip removed or a double gated wye.)

  • If a hydrant with a supply line attached won't shut down, apply a hose clamp to the supply line in order to be able to detach the fire engine.

  • In all such occurrences, immediately contact the responsible water agency to make appropriate repairs.
Using a hose clamp
to free up an engine
Using a straight tip nozzle
as a shutoff gate


Engine companies responding to a report of a flowing hydrant where debris or foreign materials in the nozzle outlet are suspected may wish to attach a gated appliance to the hydrant outlet prior to opening and closing the hydrant valve, particularly if a continued flow of water would cause property or environmental damage if the problem got worse, the flow increased and continued over a period of time.


Costs for repairing a damaged hydrant valve can run into hundreds of dollars. Don't fight with a hydrant that won't shut down. Use the resources that you have available to you in order to mitigate the problem without causing further damage to the hydrant.


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