Water hammer is cause by the inertia of flowing water. Water flows, it stops. Bang.
It might be in your case that water hammer is triggering an oscillation in ... something. A valve, pipes that arn't strapped down?
There could be a dead end in the system (essentially a hammer arrester) that is full of air which water is sloshing into and shaking in the process.
What I think I'd try to do is isolate the cause. E.g. if you turn off the service valve into the house can you trigger it by opening and closing the hydrant?
Maybe you are triggering a _pump_ upstream from you?
In any case, if pipes are shaking or the pressure is obviously spiking then it increases the risk of failure... so it's not something that I'd personally want to ignore.
It might be in your case that water hammer is triggering an oscillation in ... something. A valve, pipes that arn't strapped down?
There could be a dead end in the system (essentially a hammer arrester) that is full of air which water is sloshing into and shaking in the process.
What I think I'd try to do is isolate the cause. E.g. if you turn off the service valve into the house can you trigger it by opening and closing the hydrant?
Maybe you are triggering a _pump_ upstream from you?
In any case, if pipes are shaking or the pressure is obviously spiking then it increases the risk of failure... so it's not something that I'd personally want to ignore.