Something is making a mysterious noise.

So it's been awhile! Between school, homework, work, and playing with gadgets and such, I haven't gotten the time to post or make an instructable for quite a long time. But now, I'm back with a question.

I see lots of new users here, and to them I say welcome to the community! You are going to love  it here, everyone is helpful, and you'll find answers to just about everything. I also see some members here that were around when I still used instructables. Remember me? How are things? :P

Ok, so now for my question. A few weeks ago, after flushing the Toilet, a strange noise began behind our refrigerator. It was king of like a rattling, but not so much that as say, a prize wheel at a gameshow spinning and hitting something heavy. It's really quite odd. The refrigerator is a model with the built in water and ice dispenser. I googled it, and many seem to say it is something called "Pipe Rattling", but I don't think that is what it is, because it only started a couple of weeks ago and we have had this fridge for a year.

I have drawn a diagram of the first floor of our house to help you get a better understanding of where the fridge is in comparison to the bathroom and the toilet. Like I said before, the noise only occurs after we flush the 1st floor toilet. Another odd thing about it is when the noise occurs. It can make this rattling as the toilet is flushing, directly after the toilet has flushed, and it has happened up to a minute after the toilet is finished flushing and refilling the bowl. The noise goes for about 5-8 seconds each time, and it only sounds once after each flush.

We have not made any additions to the house before or since it started, have npt experienced any severe weather, and have not modified any plumbing in the house in quite a while, and never in that area of the house.

In the incredibly bad sketch I made, you can see the bathroom, and the incredibly bad drawing of a toilet. The fridge is indented in the wall so there are cabinets surrounding it.

Any thoughts on what this noise can be?

Picture of Something is making a mysterious noise.
bwrussell5 years ago
A few things can cause noise in water pipes. One that is possible is "water hammer". Hammer occurs when a valve is shut to quickly in a pipe where liquid is flowing. Basically when the valve is shut before the flow is slowed a high pressure zone builds up against the valve as the water is brought to an abrupt stop. Then when the flow is stopped this high pressure travels back up the pipe. As this high pressure wave passes through the pipes, is forced around corners, or is stopped by a different valve, it can cause the pipes to shake and knock.
I'm not sure why you would suddenly start getting hammer though. It's possible that there is some sort of build up in the pipes over time that has increased the flow rate enough to get hammer.

Alternatively, and more possible, you could be getting cavitation in the pipes. Cavitation is the formation of air bubbles in a liquid flow and it can be very noisy. Again for this to start out of the blue points to some sort of obstruction in the pipes. Besides the sound of the creation and subsequent demise of the air pockets, and similar to hammer, cavitation can cause your pipes to shake and knock.

I suspect the fridge is unrelated besides sitting near where the toilet plumbing runs. It's possible cleaning or replacing some of the pipes leading to and/or from the toilet could solve your problem. Is your water pretty hard (mineral laden)?