What causes squealing, whiny pipes

[shmokes]

My appartment has squeaky pipes.  When the neighbor flushes the toilet or takes a shower they make a loud, high-pitched squeal.  It's never been an issue, and still isn't really, but yesterday, for the first time in my life, I thought, "WTF?"  I cannot think of a scenario where water running through a metal tube could make that noise.  What causes it.  Is there any way to fix pipes like this, short of tearing up the walls and installing new ones?

[ChadTower]

Air inside them.

[boykster]

From doityourself.com

http://www.doityourself.com/stry/squealingpipes

Q: We recently remodeled both of our bathrooms. We also replaced our 40-gallon water heater with a 50-gallon one. Our ranch-style house was built in the 1950s. At times, we hear a loud, high-pitched noise, like squealing. It seems to come from the valves on the new water heater. I just had them replaced, but the noise still comes and goes. Any idea what this could be? Are plumbing lines ever bled to relieve pressure?

A:  We think the squealing sound you hear is water rushing through a restriction in the pipes. You may be able to eliminate the squeal easily and inexpensively.

As Bacall said to Bogie in "To Have and Have Not," "You know how to whistle, don't you?"

You blow air through a narrow hole you make in your mouth by puckering. If you blow less forcefully or increase the opening in your mouth, the whistle is softer. The harder you blow or the smaller the hole, the shriller the whistle.

So what's causing the whistle in your pipes? Your question provides a couple of clues.

First, you say your house was built in the 1950s. That means it may have worn-out galvanized pipes. Galvanized pipes corrode from the inside out, with large rust deposits forming on the inside surface. Sometimes chunks of this corrosion can break away and get lodged in valves or faucets.

Also, you've recently remodeled both bathrooms and replaced the water heater. Any time work is done on old pipes, you risk disturbing corrosion or sediment in the pipes.

Another possibility is that dirt may have gotten into the pipes when you remodeled the bathroom or replaced the water heater. Kevin had this problem when he plumbed his house. He accidentally got a small amount of dirt in one of the lines, and the sediment worked its way up to a bathroom shower and caused the shower to drip.

The fix for your squeal may be easy - or maybe not. To find out, here are few things to try first. Check all your water valves and make sure they're fully opened. This includes the valve at the water meter, the shut-off valve to the house and the valves to the water heater.

Next, give the system a good flushing. Your question about bleeding the lines is right on track, not for pressure but to remove gunk. Open both hot and cold valves to the tubs and all the sinks. Make sure that you remove any aerators from bath and kitchen faucets so you get maximum flow. Let the water run for a few minutes to make sure all lines have been purged.

If you think the culprit might be the line to the water heater, turn the valve to the water heater intake off and disconnect it from the water heater. Then attach a hose, turn the valve on and bleed that line alone. This will bypass your hot water lines.

If these things don't fix the problem, check the water pressure to the home, which can be done by the water company. Pressure should be about 60 pounds per square inch. Much more and you risk putting undue stress on your pipes. If the pressure is too high, you may have to install a pressure reducer in the main line. This is a job best left for a plumber, unless you are skilled with a pipe threader and soldering torch.

[shmokes]

Hmm . . . well, I might try a few of those things, but since it's an apartment, and one that I will be leaving in less than half a year, I probably won't put too much effort into it.  It's good info for the future, though.  Something tells me I won't have heard the last of squealing pipes when I leave my current place.