I noticed that some pipes have a low flow of water, in particular hot water pipes.

I removed the limestone from faucets using vinegar, and it worked, but I noticed that the supply pipes themselves are obstructed (probably by limestone?).

In particular, the pipe that brings hot water for the bidet has a very low flow. I know it for sure since I let the water flow directly from the pipe, without the faucet.

What can I do to remove limestone from that pipe? Can I pour vinegar in the water boiler? And how? I have an old Vaillant VCWI 240 E gas boiler.

  • What is a "loading plumbing system"? Is this the supply lines where you get water from the city/well?
    – FreeMan
    Nov 13, 2023 at 18:02
  • @FreeMan Yes, from the city. Nov 13, 2023 at 20:54
  • Rather than "limestone" you should probably use the term "mineral deposits" or mineral scale. Dec 20, 2023 at 21:27
  • 1
    Most of the adhering deposits would be in the boiler. Some more might be in the exposed hot water line immediately after the boiler. You probably would not have to open up any walls to remedy this Dec 20, 2023 at 21:29
  • @JimStewart that's what I discovered by myself... if you do an answer, I'll accept it. Dec 21, 2023 at 15:29

2 Answers 2


Most of the adhering deposits would be in the boiler. Some more might be in the exposed hot water line immediately after the boiler. You probably would not have to open up any walls to remedy this.

As far as the advisablility of using vinegar to descale the boiler, that would depend on the design of the boiler and the recommendations of the manufacturer. Modern tankless water heaters are supposed to be descaled with vinegar; they are designed to withstand this.

  • Thank you. I prefer to not risk, since the boiler is a gas one and they will be out of law in Europe by 2040. I'll buy a new heat pump boiler. Dec 21, 2023 at 19:09

Replace the pipes and, if it's time, the boiler.

There's no easy or practical way to clean mineral deposits from the inside of pipes, and in any event you would have to remove them and soak them in chemicals and/or run stiff brushes through their insides. Once you bite off the need to remove and replace the pipes, it makes a lot more sense to replace them with new ones. Use polyethylene pipes as they are more resistant to the problem.

Strong chemical solvents in your pipes can get into your drinking water. Unless your bidet has his whole own plumbing system, you can't do that.

Look on YouTube to see what the inside of a very calcified hot water heater looks like. You will quickly understand why you can't reverse that with vinegar and I hope you'll agree that using stronger chemicals is a bad idea, not to mention expensive.

A water softening system can delay this problem happening again.

Probably not the answer you were looking for, and if it seems drastic, think about the long-term plans, so if / when you do a bathroom renovation you can include a more extensive plumbing refresh at that time.

  • You're right: not the answer I'm looking for :D No way I'll destroy half house to replace the pipes. Nov 21, 2023 at 19:59
  • I'm curious, when was the house built and the bathroom last renovated? I've lived in houses with very hard water, kettles need descaling monthly, toilet flappers need cleaning a few times a year, shower mechanisms last 20-30 years max, etc ... but copper pipes 60+ years old are not clogged by scale, and 80+ years old eventually fail for other reasons.
    – jay613
    Nov 21, 2023 at 20:03
  • The house is 34 years old. Not sure it's the limestone the problem, only a guess. I usually put the aerators in vinegar and clean the filters when it's time. The hardness of the water of my city (Rome) is 30,4 °F on average. Nov 21, 2023 at 20:24
  • Is the piping copper tubing or is it something else? If it is copper tubing, are the joints soldered (aka "sweated") or are they crimped? If they are soldered, is it with lead solder? If you have lead soldered pipes and you use acid to try to clear them, you could reduce passivation and get leaching of lead into the water. Usually the mineral deposits are in the boiler and very little in the pipes. Heat causes the precipitation of minerals at the first encounter of heat. However you can get "pinhole" leaks in copper tubing in the hot water line. Dec 20, 2023 at 21:10

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