Plumbing question?

We just moved into our newly purchased 1987 house. Its a split level with a basement with 2 bathrooms. Any time we turn on ANY of the water faucets, or showers or flush in the house, we can "hear" it in the entire house. There is no leakage anywhere and all the faucets deliver good pressure of water. But the noise is annoying, especially at night. Is this common? Is there any problem with the plumbing? I have heard a term called water hammer, is this noise related to that? What can be the remedy? Thanks for sharing your experiences/solutions. Going by the info about water hammer provided by many of you below, I must add that my problem is not related to water hammer.

Public Comments

1. Water hammer is when a hammer like noise comes from the pipes, someone beating on the pipes with a hammer. But as far as always hearing the water, i.e.e, running water, etc. its probably just poorly insulated wall cavities allowing the sounds to be heard outside the walls. If its a hammering sound, then you can install a device to stop that which is sold at most home improvements centers.The other problem is more involved, open walls, insulate pipes, repair walls and or ceilings. Good luck.
2. Water hammer occurs when a valve is shut off rapidly and the moving water in the pipe comes to an abrupt halt, causing the hammer sound. Little bladder tanks and stubs of copper upside down act as hammer arrestors and are usually installed in most plumbing systems. Maybe adding a small tank somewhere in the plumbing may help.
3. It may be because the pipes aren't bracketed properly and are banging against the inside of the walls. Check in the crawl space and see if they are bracketed. A simple trip to Home Depot could cut down on some of the noise but if the pipes that are behind the walls are not bracketed then you would have to go through the dry wall to bracket them. Try bracketing the pipes that are exposed and see if that helps before cutting into drywall.
4. Your noise may be caused by flooded air traps. These are the gizmos that prevent the 'bang!' of water hammer by acting as shock absorbers. But, if they fill with water (which can happen over time) then you can get weird noises. Try draining your water lines: turn off the water to the entire house and open a faucet at the lowest point in the basement. Then, open all the other faucets in the house and allow the water pipes to drain completely. After a few minutes the water will finish draining out and you can close the bottom faucet. Turn the water to the house back on and shut off the other faucets once the air is purged and water is flowing normally. Also, make sure all vales are fully open (a half open valve can make a lot of noise!) .
5. If it's the sound of running water you hear, it's likely a lack of wall/floor insulation (floor insulation is 'acoustic' insulation, the stuff in walls is thermal insulation: they 'look' similar but have different properties). re-insulating inside walls and floors or ceilings is expen$ive and messy. If it's air-hammer, you can try this free and often-effective remedy: turn on ALL of your water taps, tubs, showers, outside faucets, etc. Let them run for a minute, then starting at the faucets that are at the lowest level, especially a below-ground basement, turn the taps off slowly and completely, Then go to the next level and do the same, finishing at the highest level in the house. This is to allow any air in the pipes to float upward and out of the water supply pipes, since air bubbles rise. You should also drain a few gallons of water out of your hot water tank during the above procedure, and look at what comes out, noting any rust, dirt, 'calculi' (hard water minerals, lime, etc.). Drain a few gallons out of the hot water heater once or twice a year.
6. Water hammer would sound like a bang or thump immediately after flow was stopped. It's the rebound energy wave of the water stopping as the pipes return to full pressure. What you are describing seems to be the sound of the water actually flowing through the pipes, which is caused by water flowing at high rates of speed and/or through restrictions in the lines. I would guess that some of your pipes are too small in diameter for the amount of flow they're supporting. First, check all of your water valves and make sure they are fully open so there's no restriction in the supply. Then have a plumber check the pressure and/or flow rate at the fixture that's furthest from your water main. If this is excessive, then your plumber can install a pressure-reducing valve (PRV) on the supply line to reduce flow. In drastic cases, you may need to replace a section of pipe to permit the same volume to flow at a lower velocity.
7. I agree with plain jane, it's likely an insulation issue. Split levels are tough to address this issue, though. I'm guessing that the ceilings are "finished" with drywall or some other permanent material that would prevent you from gaining access to the piping and putting in insulation around it.