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Plumbing Mysteries

I’ve been perplexed by the behavior of our plumbing system recently.

About a month a go I noticed a loud, intermittent rattling sound that seemed to emanate from the cold water inlet pipe on our water heater. Turning the valve stopped the rattle but obviously would cut off our hot water as well. The sound is coming from where the pipe is exposed; I don’t believe it’s rattling against a floor joist or some such.

At the same time I noticed the water tube running into our ice maker was rattling as well. It always gave a “kick” after we ran the kitchen sink faucet, but now it was vibrating on its own — quite violently at times.

And a third thing. But this gets kind of complicated. The upstairs toilet has flapper issues. I’ve had to replace the flapper on an annual basis. The old flapper no longer holds its seal for whatever reason, and water leaks through from the tank to the bowl, causing the float to sink and the valve to run intermittently. I have a devil of a time finding a flapper that fits. This time, since I was at Ken Brown’s getting a heater, I had professional assistance. They helped me find the model number for our toilet (it’s a Kohler) and supplied the proper flapper. It should work. But it doesn’t quite hold the seal. So the valve runs.

That’s probably a completely separate issue from the rattling, except that when the valve runs, there’s a noisy rattle in that pipe too.

So we have rattling in three different place throughout the house.

Also I noticed a lot of air bubbles on the flapper. That might not have anything to do with anything, but I don’t recall seeing it before.


I’ve done some net searches. At first I thought we might have “water hammer.” But it seems that’s a loud bang when you shut off a faucet (or, you know, any valve). Our noises just come and go intermittently, with no seeming pattern. But now I’ve had another idea: Perhaps the running of the toilet is causing a hammer. If that’s the case, shutting off the upstairs toilet should end the rattling.

So I’m testing that theory now. It will take a while because sometimes the noises go away for hours at a time.

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  1. O’ Plumbing! How is that I so despise you? Even more so than electrical which can kill me?

    Whatever you do, don’t attempt anything until Monday. I once started a plumbing job on the Friday afternoon of a holiday weekend and had no water until the following Tuesday.

  2. The air bubbles clinging to the inside of your tank and to the flapper are most likely the result of high pressure water from the supply line churning air into the water as it fills. Try turning the toilet’s water supply valve down a bit (about half) to decrease the pressure of the water coming into the tank.

    The water pressure issue might be causing your banging noises as well.

    Pipes usually rattle and bang when a valve closes very quickly and suddenly blocks off a large amount of fast moving water. The force of that water slamming into the now closed valve is going to cause the pipes to shift around for a moment. Over time it will also cause damage and leaks. So you want to minimize it.

    One solution that may not require a professional plumber is to decrease the flow of water to the problem areas by turning the valves down like I recommended with your toilet. This will affect your water pressure and probably get rid of the noise. You can experiment with different levels of flow to get the highest water pressure without the banging.

    For the other options I recommend calling in a professional to either,

    1. install a shock absorber (a pipe which takes the brunt of the water force when the valve slams shut),

    2. replace the line leading up to the valve with a spiral of copper pipe (acts sort of like a flexible spring to discharge the momentum of the water),

    3. install an expansion tank for the cold water before it enters the heater, or

    4. install larger pipes in the whole house to slow the water down.

    Good luck and feel free to contact me at to vent and bounce other problems off of me. 😉

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