Initial hammering Sound when open Tap

After replacing lot of valves and able to open all faucets. Hopefully took all air out. Now I get a hammering sound for a few seconds when we open almost any tap but then quickly dies. If one tap is open and then open another one then no sound.

How to fix the initial hammer sound? Any help would be appreciated ...

If a valve is still bad (One before or after ) the meter then the sound should stay all the time?

Is it possible air is still trapped?

What does the pressure gauge say for static pressure when everything is off?

Do not have a pRessure gauge but pressure looks fine .. Do you think installing expansion tank on Water heater or a Water arrestor will make any sense?

gmohan123 said:

Do not have a pRessure gauge but pressure looks fine .. Do you think installing expansion tank on Water heater or a Water arrestor will make any sense?

Click to expand...

If I tell you to install anything, I'm trying to fix your problem by fixing symptoms.

I'm trying to get to the problem, the source of the symptoms you're having.

You cannot look at water flowing through a faucet and know the pressure, otherwise you would of shot me a true number on how many psi it was.

Contact your water utility company and ask them for the range of pressure you're in.

If you're in a safe range, then I can tell you the next step to solve it. Anything else and I'm shooting blind without having the concrete proof if it is or isn't high water pressure.


High Water Pressure

Thermal Expansion

I called them it is around 65PSI and they said it is in teh safe range. Any help you can provide will really help me ...

Okay given the water pressure is fine (normal range) and you didn't have these problems before the replacement of valves, go around and isolate every single valve replaced by shutting it off and determining what removes the sound.


IF, by any chance this doesn't resolve the issue then you need to see if any existing valves were shut off, causing the issue.

Fill valves inside toilets if they ever get dirt inside them will cause issues like you are experiencing.


I just got back from a kitchen sink faucet install where I bled off the valves leading to the faucet to make sure they are clear, run water through it and no water pressure.

Turns out that all the scale inside the pipe moved through the hose leading to the pull out spray and Aquasource made a hose you cannot clean.


Had to take the faucet back out and I have to pick up a Delta.

Dirt or loose washers can be a culprit in your scenario but I needed to make sure first that there wasn't a water pressure issue.