What Causes Green Corrosion On Copper Pipe?

green corrosion on copper pipes

Are you searching for what causes green corrosion on copper pipe of heating systems? For people who experience cold winters, central heating can be a necessity rather than a luxury. For those new to heating systems, you may notice that the pipes of your heating system develop a green color in certain places.

Copper Pipes are mostly used for water heater pipes, which can oxidize in damp or moist conditions. The green color on the pipes is where the pipe has had prolonged exposure to water or humid conditions, forming oxidation on the copper. It is a form of corrosion and can damage the pipe in extreme cases.


What Does Green On Copper Pipes Mean?

We have all seen copper piping that has a green or greenish-blue powdery type substance on the pipe. This is known as oxidation and generally occurs when the copper pipe is exposed to a combination of water and air or oxygen. This oxidation can indicate a potential problem with your pipes, which could lead to a pipe failure if not thoroughly checked.

Why Do Copper Pipes Turn Green?

Heating Systems use copper pipes in preference over other materials because copper is a metal that conducts heat very well. Hot water is circulated through the copper pipes, and the metal absorbs the heat from the water and radiates it into the air in the room, warming the air or the floor if the heating is underfloor piping.

Once the copper has absorbed the heat from the water, it stays hot for a long time, making for an efficient heating mechanism and keeping the water hot as it circulates through the piping throughout the house.

This heat-conducting property of copper makes it the perfect choice for a heating system that uses radiant heating to warm a home.

The green color that appears on the pipes is a form of oxidation that occurs when the pipe comes into contact with moisture and air. It can be likened to rust on steel, which forms under similar conditions on unprotected steel.

Like rust on steel, oxidation on copper pipes is corrosive, and if the problem is not rectified, it could result in the pipe corroding to the point that the pipe will fail.

A location that you will frequently see this type of discoloration is where the pipe goes through a brick and mortar or concrete wall. Any damp or moisture within the wall can result in the copper pipe oxidizing and turning green.

This may not indicate a problem with the pipe but could be a symptom of damp in your wall that needs addressing.

Do Green Copper Pipes Need To Be Replaced?

The green oxide that forms on copper pipes exposed to moisture and air is not a harmful substance despite its acidic appearance. The substance is actually inert and is not toxic, but it does indicate a potential problem for the pipe the requires attention.

Green heating pipes do not necessarily need to be replaced, but if you see oxidation on the pipes, you should investigate to find the source. It could result from a pinhole leak in the pipe, faulty join, or dampness in a wall. If the corrosion is significant, the pipe may need replacement.

If the oxidized pipe is left, the leak could worsen, resulting in a burst pipe, or the corrosion of the pipe could weaken the pipe to the point that it bursts. Either way, if you see green oxidation appearing on your central heating pipes, it is unlikely to be an emergency but warrants investigation to locate the cause for the oxidation.

The time it takes for copper pipe to oxidize is fairly lengthy, so if you have not noticed a leak by any dripping or pooling water, the problem is unlikely to be severe. You probably have some time to sort the issue out, but you should not leave it indefinitely.

How to Remove Green Corrosion From Copper Pipes?

Copper oxidation can be removed from the pipes in several ways. A light solvent or light acidic solution with a light abrasive rub, such as salt, will generally remove the oxidation. There are many recipes for cleaning recipes for copper pipes. The strategy to prevent oxidation is regular cleaning.

Cleaning green oxidation from copper pipes does not require expensive or dangerous chemicals. One effective way to clean the oxidation from the pipes uses ingredients that you will easily find in your kitchen cupboard.

The ingredients required are as follows.

  • White Vinegar
  • Salt
  • Flour
  • Baking Soda

Mix equal parts of the vinegar, flour, baking soda, and salt to form a paste. Rub the paste to cover the entire affected area of the pipe and allow it some time to dry; up to 30-minutes should be sufficient.

After the required time has elapsed, wipe the paste off the pipe with soapy water. The alkalinity of the soap will neutralize the acidity of the vinegar. Dry the pipe well after cleaning; otherwise, the oxidation process will quickly restart, requiring more frequent cleaning.

Salt by itself is a good method for polishing copper and removing oxidation. Sprinkle some salt onto a damp cloth and rub the salt vigorously over the oxidation. Wipe the salt off the pipe with a clean part of the damp cloth and dry the pipe well.



Another Method to Remove Green Corrosion On Copper Pipe

Another method that works very well for severe discoloration and oxidation buildup is to use a piece of light grit emery cloth to rub the oxidation off the pipe until the clean copper beneath is revealed. 

Dab some acetone on a rag and wipe the oxidized area of the pipe with the acetone. Once the pipe is clean, use a wet, soapy cloth to wipe the acetone from the pipe. Dry the pipe thoroughly after cleaning.

Acetone is a flammable substance, so don’t use it near any open flames. Acetone can also be bad for your health, so use a respirator to prevent breathing the fumes in, and wear rubber gloves to protect the skin on your hands.


The green discoloration on copper pipes is an inert substance that is not harmful to humans. However, the presence of heavy oxidation can indicate potential problems on the pipe or where the pipe is located.

Light oxidation usually is not a cause for concern, as it can be a reaction of the copper to the moisture in the air. Heavy oxidation can indicate a leak in the pipe or a join or damp conditions in a wall. In this case, it is important to establish the cause of the oxidation.

Oxidation on copper pipes can be unsightly, but fortunately, there are many recipes available using standard household ingredients to remove the oxidation and restore the color of the copper piping.