My home is 16 years old and I have never experienced water hammering or banging pipes until recently.
No plumbing changes have occurred either. About 18 months ago we put in a new dishwasher and washing machine.
When the hammering occurs it seems to be directed mostly by/near my refrigerator that has a water line for water dispensing and ice making.

Typically the hammering occurs when water is run in the bathrooms on the 2nd floor and I have began to notice it happening after the washing machine fills up. Again, the hammering seems to be directed near the refrigerator on the 1st floor.

Not sure if I have an issue with one of the appliances or something else with the plumbing. The problem is very frustrating....any guidance is welcomed.

Thanks!

do you have a pressure reducing valve at your water main.
perhaps it has worked all these years and is now malfunctioning causing higher pressure which in turn can cause water hammer ??

Thanks Packy...I do have a pressure reducing valve. I was thinking it may have debris in it. Maybe thread the screw up so many turns and then screw it back down the same number of times.



Edited 1 times.

get a hose pressure gauge and check the pressure.
they are readily available and not expensive.
I'm only guessing at what the cause of your water hammer is.
checking the pressure is a good place to start.

My pressure is at 72psi, which seems high. Again, this has not been touched since installed.

lower it down to 55-60 PSI.
see what that does for the water hammering.

I did. Still occurred. The hammer sound always seems to come from the refrigerator. Could I have a bad inlet valve which could cause the hammering? Running water on 2nd floor seems to vibrate my refrigerator. I've even seen my water filter inside the refrigerator vibrate when the hammering occurs. That is why I'm thinking it could be a valve on that

Do you have a thermal expansion tank on the water heater? If so, it may be waterlogged (bad).

No I do not have a thermal expansion tank.

if the valve on the refrigerator is bad it will only cause water hammer when it actuates. when the valve is just sitting there closed it has zero effect on he rest of the water piping.
just as a test, dial your pressure down to 45 PSI to see what happens.

Thanks for the clarification on the refrigerator valve. When I lowered my pressure yesterday, I put it at 50psi. Do you think a further reduction could help? The occurrence is so random on when it happens and what is being used, makes it difficult to pinpoint.

Is the "hammer" occurring when water is being run through a fixture or when the fixture is turned off?

The hammering occurs when a fixture turns off. I have heard it when the bathroom on the 2nd floor (showers only) is used as well as when the washing machine fills up. The noise does not occur every time the water is turned off in these locations. No other fixtures in the house cause the noise.