When the shower is running and someone turns on any tap or flushes any toilet in the house, the shower pipes begin to vibrate making a pulsating knocking kind of noise. The showers have the water regulators and the shower water controls are the single dial turning type. So usually we turn the dial half way so that it's not cold, nor hot, but warm. This is usually when the vibrating also happens. Then if we turn the dial to cold (or hot) then slowly back to the middle for warm, the vibrating stops (sometimes). And again if someone uses any tap or toilet, it starts vibrating again.

The house is 3 years new and we can't remember when it really started. We think it may be the water pressure needs to be adjusted somewhere, but we're not sure. Any help would be truly appreciated.

Hey Scorp,

It sounds like a diverter is vibrating in the shower valve due to a drop in pressure but since you failed to give us any details about the make and type of shower valve, (just shower or tub and shower valve?) this is about all the help we can give at this time. If you come back with more details to work with we'll try to give you a better answer. Regards, Tom

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Originally Posted by Scorpion88

When the shower is running and someone turns on any tap or flushes any toilet in the house, the shower pipes begin to vibrate making a pulsating knocking kind of noise. The showers have the water regulators and the shower water controls are the single dial turning type. So usually we turn the dial half way so that it's not cold, nor hot, but warm. This is usually when the vibrating also happens. Then if we turn the dial to cold (or hot) then slowly back to the middle for warm, the vibrating stops (sometimes). And again if someone uses any tap or toilet, it starts vibrating again.

The house is 3 years new and we can't remember when it really started. We think it may be the water pressure needs to be adjusted somewhere, but we're not sure. Any help would be truly appreciated.

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I just installed a Danze shower unit with valve model D113000BT and I'm having the same problem with pulsating and knocking when someone uses the sink. I pulled the valve apart and checked for debris and there was nothing. Could it be that the spring in the diverter is not strong enough? Please help, Darrell

If you suddenly cut off or start a large flow in a pipe, you get something called "water hammer", which sounds like your pipes knocking around for about a second. The solution here is to change the flow more gradually,rather than cause sudden changes.

Sustained vibrations are also possible. Any pipework can resonate at a given frequency due to a phenomenon called flow-induced vibration. The effect is similar to singing a note and having a guitar string at the same frequency also start to vibrate sympathetically. In the case of your pipes, conditions may be just right for pressure variations in the pipework to bounce from end to end and cause the pipes to resonate. My shower at home does this if I have the water at just the right flow rate. Any slight increase or decrease in flow and the vibration stops. Thus, a small change in a valve position may "cure" the problem.

If you have shutoff valves on a toilet, for example, make sure they are full-open (they may be less likely to leak that way,too), since a cracked-open shutoff valve is a sure-fire way to induce vibrations. It is less likely that you could have a loose washer, or some obstruction (I've seen bits of solder) that is helping to vary the flow rate, and set things vibrating.

If all else fails, you can try installing a tee in your line with a vertically oriented length of pipe off the side of the tee that is capped. An air cushion will remain in the dead-ended pipe when the system is refilled, and this cushion should dampen any adverse effects from water hammer or flow-induced vibration.