What causes a loud tapping noise when water is turned on each morning from upstairs bathroom and the sound is coming from the drain pipes?

Answer 1

It may not be the 'drain' pipes. The noise is more likely to be coming from the water supply pipes.

Sometimes called 'water hammer,' such a noise is caused by vibrating inflow pipes. When the water is turned on in the upstairs bathroom, the water surges through the pipes to the tap. Generally the pipes don't move much when this happens, but sometimes a pipe is not supported at key points and it is free to knock against the structure of the house, perhaps against the floorboards or supporting joists. Or maybe they rattle against each other, or against brickwork.

Sometimes it is a worn washer in the tap that causes the vibration. A washer in good condition will allow the water flow to increase gradually as the tap is opened, but a worn washer may not allow this to happen in a steady controlled way. The result is that, at a certain point in turning the tap on, and when it is not fully on, a vibration is set up, and this rattles the inflow pipes.

IDENTIFYING THE CAUSE AND STOPPING THE TAPPING is not always easy! If the washer, and the tap, are both in good condition, you need to identify and locate the actual cause and place of the noise. This may mean lifting floorboards, or otherwise gaining access to the pipe system. Then some sort of support and/or firm cushioning material needs to be put securely in place to prevent the pipe knocking against whatever it is that it is knocking against!

If such a task seems too daunting, you'll just have to call in a handyman or plumber!

Other possible causes of water hammer:

• the water pressure is too high
• pressure chambers, if fitted, need clearing

There are ways to check and resolve these possibilities. Maybe the water pressure needs to be reduced. Or maybe the installation of a water hammer arrestor will solve the problem.

WHATEVER the situation, get it fixed! If not resolved, water hammer can lead to loosened water joints, leakage, flooding, water damage, and structural damage.

TO FIND OUT MORE, you may wish to do more research online. Enter 'water hammer' in a search engine such as Google and you will be presented links to some helpful articles.

In 'Related links' below we have included one of those links which you may find useful.