I have a mixer tap in the kitchen that has been causing an increasing amount of water hammer sounds in the pipes in my utility closet and behind my wall. There is almost no way to shut off the tap without causing the sound, even if done softly.
A plumber who just visited insisted that the problem is with the tap itself, whose valves appear worn out, and replacing the tap would solve the water hammer issue.
To demonstrate his point he had me notice how no other tap in the house causes the water hammer sound even if shut off violently.
When I mentioned that I heard others suggest that installing a water hammer arrestor on the affected pipes is a potential solution, he said that he considers it an expensive solution that's not worth the effort, and that the tap would remain an active issue.
Before engaging in an unnecessary tap replacement, I wonder if his assessment checks out—will replacing the tap actually solve the issue as he says, or will it prove a temporary or incomplete solution?
EDIT: The same plumber just came here again and we found a complication. Changing to a different tap didn't stop the water hammer.
He had a look in the crawlspace beneath the house and was able to identify the pipes that are shaking, and will now fix them in place with some expanding foam.
But I'm worried that fixing the noise won't reduce the risk to the pipes themselves. Can my pipes still silently fail due to the pressure? Replacing the faucet didn't seem to stop the water hammer issue, so will the pipes keep deteriorating even once we've fixed the sound?
Best Answer
My answer is based on this:
It sounds like the plumber properly diagnosed the issue and can see that the valve is worn out. The more you use it then the more worn out it gets thus explaining the increasing amount of water hammer.
If the issue can be solved without a water hammer arrestor then I would go for that solution. Consider the pros of not installing an arrestor:
If you install an arrestor then you're only hiding the problem.
Yes, the arrestor will absorb the noise but all that water force is still being exerted in your pipes. If you're only taking care of the symptom then the water hammer can still cause joints to fail and then you'll have a much bigger problem on your hands.