How to Descale/Remove Calcium Buildup From Pipes

How Do I Descale my House Pipes?

If you live in an area with hard water, scaling up of pipes by hard water mineral deposits will always happen. This is especially the case if you have steel water pipes. Plastic and copper are also affected but not as much as steel.

The mineral most responsible for scaling water pipes is calcium. Calcium, also known as limestone will also settle at the bottom of the water heater and clog shower head and faucet aerators.

clogged water pipes

Descaling pipes is the process of removing accumulated mineral deposits inside pipes using natural descalers like vinegar, or chemicals likes acids and bleach. Hydro jetting can also be used to descale badly clogged pipes.

To descale your water pipes, start by turning off the main water shut off valve then turn off the water heater valves. Drain the water already in the pipes and replace it with a mixture of vinegar, baking soda and hot water. Wait for about 6 hours then flush the pipes.

The best and long-term method of descaling your water pipes is by the installation of a water softener. A water softener removes hard water minerals before they get into the pipes thereby preventing formation of limescale and staining of toilets, sinks and bathtubs.

Chemicals like acids, lye and bleach can also be used to descale water pipes. They work faster than vinegar and baking soda but are toxic to the environment, could damage water pipes and are unsafe for your health.

You should especially avoid using chemicals to descale your pipes if you use water from a well. The chemicals can end up flowing back to your well and contaminate your drinking water.

If you need a professional to descale your pipes especially when they are badly clogged by hard water minerals, hydro jetting is one of the methods to use. This involves the use of pressurized water to obliterate the scales.

It costs anywhere between $300 and $600 to descale your pipes depending on the amount of work involved, the method used and your location. If you decide to descale the pipes yourself, it will only cost you your time and the cost of the descaler.

How to Get Rid of Calcium Build Up/Limescale from Inside Pipes


The main sign that your water pipes needs descaling is low water pressure in the house. The limescale and other minerals like iron and manganese clog the pipes, restricting the flow of water and hence the low pressure.

To descale your pipes, you have to first answer the following questions:

  • Is the problem only affecting one fixture or all of them?
  • Are both the cold and hot pipes scaled?

If the problem is only affecting one fixture (like a sink or shower), the problem is relatively easy to fix. However, if the problem is affecting more than one fixture then you will need to descale all the pipes.

If for instance the low water pressure is in the bathroom or kitchen sink, the problem could be a clogged aerator. A faucet aerator is the attachment at the tip of the faucet. It allows water to mix with air to prevent splashing.

The tiny openings on the aerator are easily clogged by mineral deposits and pipe scale thereby reducing the water pressure in the faucet. At times, the cold and hot faucet water supply lines under the sink could be the problem.

The same is also true for shower heads. The holes get easily clogged by calcium deposits thereby lowering the water pressure in the shower.

1. How to Flush your Sink Water Lines and Clean Aerators

Let us start by cleaning the aerator.

  • Disconnect the aerator from the faucet. In some faucets, you will only need to grab the aerator with your bare hand and turn it counterclockwise. You will however need a wrench or pliers in others. To prevent scratching the finish off the aerator, wrap a rag around it first.
  • Disassemble the aerator. An aerator has a few parts as is explained in this post. Drop the parts in a bowl then pour in white vinegar until they are completely submerged. Wait for about 15 minutes.
  • Turn on water on the faucet. Check if the pressure is okay without the aerator or if it is still low. If the pressure is good, the aerator was the problem. Otherwise you need to flush the water supply pipes.
  • Use an old toothbrush to scrub the aerator screen until you have gotten rid of all the limescale.
  • Put the aerator parts back together and connect it back. You don’t even need to tighten it with the wrench.

If a clogged aerator doesn’t seem to be the problem, you can try flushing the water supply pipes. Make sure that you have removed the aerator before flushing the lines; otherwise all the minerals will end up clogging them.

  • Turn off water to the faucet by turning the 2 shut off valves under the sink all the way clockwise.
  • Turn on the faucet to drain the water already in the lines.
  • Have an empty bucket nearby.
  • Disconnect the water supply lines from underneath the faucet and place them inside the bucket.
  • Turn on the shut off valves and flush them for about 30 seconds.
  • Turn off the water and connect back the water supply lines to the faucet.
  • Turn on the shut off valves and check if the water pressure has improved.

That is the same method you would use to clean a clogged shower head. Just disconnect it from the shower arm and sock it in a bowl full of vinegar for about 30 minutes before scrubbing it with a brush. Check out this post for more details.

2. How to Descale your Hot Water and Cold Water Pipes

If you want to descale your water pipes naturally, you will need baking soda and vinegar in the ratio of 1:2. Vinegar is the most important product in this and you don’t always need baking soda but I like adding it in the mix.

Usually, 2 gallons of vinegar should be sufficient but you can use up to 5 gallons. Just remember to use a half amount of the same baking soda.

This is how to do it:

  • Turn off your main house water shut off valve. This valve will most likely be located in the basement, crawlspace or an outside wall, usually in the side of the house facing the street. It is always very close to the water heater.
  • Turn off the water heater.
  • Turn off the water heater hot water shut off valve. This will prevent any hot water from flowing to the house.
  • Turn on all faucets in the house and let them run until all the water in the pipes has been drained out. Flush all the toilets as well.
  • Link the cold and hot water pipes using a garden hose. Since the descaler will be inside the water heater, we need to do this to descale the cold water pipes as well.

Note: To cross the hot and cold water pipes, turn on one hot water faucet and another cold water faucet. Connect the 2 faucets using a garden hose.

  • Turn off all the other faucets.
  • Drain the water heater. Since the water heater is already full of water, we need to drain out some water first. Connect a garden hose to the drain bib and drain out a few gallons of water. The level of water needs to be below the temperature and Pressure relief valve (T&P) by about 5 gallons.
  • Disconnect the T&P valve. Before that, raise the valve handle just to be sure that the water level is well below the valve. You don’t want hot water gashing out once you remove it. Use a wrench to disconnect the valve.
  • Use a funnel to add the baking soda inside the water heater. Use the same funnel to also add the vinegar inside the tank.
  • Connect back the T&P valve. Don’t forget to wrap Teflon tape around the threads to prevent it from leaking.
  • Turn on the water heater shut off valves (hot and cold).
  • Turn on the hot water faucet farthest or highest from the water heater. As soon as water with that vinegar smell starts to flow out at a high pressure turn it off.
  • Wait for about 6 hours or longer.
  • Turn on main water shut off valve.
  • Turn on water heater.
  • Drain the pipes. Turn on all the faucets (remove the garden hose linking cold water and hot water pipes) until the vinegar smell disappears from the water.
  • Turn off the faucets starting with the one nearest to the water heater and finish with the farthest one to prevent air lock in the pipes.
  • Check if the water pressure and quality has improved.

Tip: While descaling pipes using this method, it is important to first remove all your faucet aerators. That will prevent them from being clogged by the calcium broken down by the vinegar and baking soda.


As I had mentioned, chemical cleaners are another option to consider if that is the path you want to take. The chemicals come with directions for use but the process to introduce them into the pipes is as described above.

If you however feel like the above outlined process has not done enough descaling, you can always hire a plumber to do it for you. Plumbers have more experience and better tools to do the job than yourself.

Leave a Comment