My water pipe frequently vibrates whenver you flush the toilet nor turn on the water... it usually last for 3-5 seconds and it will shut off by itself. Sometimes I turn on the water to stop it because it very annoying especially at night time. Previuosly it was happening if we use the main washroom but now it seems that any toilet or water pipe is been used would cause the vibration. I am just concerned about it since it's been almost a year now that were having this problem... could you please help me! Thanks for your attention.

This may help if your house is under 45 years of age.
Back in the 60's we were required to to put air chambers on all bath lavatories and kitchen sinks. Over time water and condensate built up in them and they must be recharged. First turn off the house at the main house shut off valve. Then open hot and cold faucets at the farthest bathroom to prevent air lock.(This is important.) You will find under each fixture little brass or chrome valves. These are called angle stops. With a small pail held under the angle stop to catch the run off look under the handle of the stop and you will see a nut with the stem running through it. This is called the bonnet packing nut. Put your wrench on it and back it off counterclockwise. Now open the stop and remove the stem and washer assembly, The stop will began to drain. When it has quit draining reassemble the stop and move on to the next one. Do this on each one of your angle stops. There will be six of them in a two bath home. When you are done, close off the faucets you have opened, turn on the water to the house, and give yourself a pat on the back.
You have just recharged your air chambers and saved yourself a hefty service call bill. Hope this helps you out and thank you for rating my reply. TOM

Do you have a pressure regulating valve?

Do you have a pressure regulating valve?

I am not sure... where could I find that if I have it?

Should be just after the main shut off valve.

When you hear noise feel here for viabration in that area of pipe. Vibration could mean faulty PRV.

You can also have loose washer in your faucet or angle stops. But first, I would Close and Open each angle stop under your sinks and toilets. See if this helps...

Do you have a pressure regulating valve?

Yes