How To Remove Corrosion From Water Heater Pipes

Corrosion is an issue that can decrease the lifespan of water heaters. It can cause appliances to break down and lead to severe health hazards. Every appliance in your household that needs warm water can be affected by corrosion.

Pipe corrosion can have several different reasons. You might question how to remove corrosion from water heating pipes? 

From brushing and draining the rust to replacing sacrificial anodes, you can try a bunch of different methods to remove corrosion and rust from your water heating pipes. In the worst case, you might have to change the water heater. Keep reading to know more!

How To Remove Corrosion From Water Heater Pipes

What Are The Causes Of Pipe Corrosion?

The hot and cold water intel is usually located at the top of the water heater. These fittings are made out of copper or steel.

The combined presence of oxygen and water lead to an electrochemical reaction, causing the pipes to corrode.

When this happens, it is known as galvanic corrosion.

Manufacturers usually use special fittings with a plastic tube within the steel pipe. This plastic tube prevents the steel pipe from coming in contact with the water.

However, these fittings might develop imperfect internal seals at the ends. If the water leaks through this seal and reaches the metal, corrosion can occur. Galvanic corrosion can dissolve the steel pipe threading in the copper fitting and cause leaking.

In addition, corrosion can result from mineral build-up or a sudden change in the water direction. It can also occur from issues that affect the sacrificial anode rod.

The anode rod is a long rod that prevents the walls of the water heater from rusting. When this rod fails, sediment collects at the bottom, causing corrosion.

How To Tell If Your Water Heater Pipe Is Corroded? 

Corrosion in the pipe usually goes unnoticed unless you experience issues with the water supply. If the water from your taps is cloudy or contains particles of mineral flakes, or has a weird taste, the chances are your water heater pipe is corroded.

A restricted water supply can also be a sign of corrosion. Corrosion at the junction between the steel and copper fittings can indicate galvanic corrosion.

Calling a plumber whenever you experience such issues with the water is the best way to know if your pipe is corroded.

Professionals can examine the different components of your water heater and run different tests to conclude if the pipe is corroded or not.

They can make appropriate adjustments to stop the leaking and rust. It is advised to have your water heater serviced at least once a year to prevent such situations.

How To Remove Corrosion From Water Heater Pipes?

If the corrosion is not too severe, you can remove it yourself using the following methods.

Brushing And Draining The Corrosion

Empty the tank and unscrew the drain valve using a wrench. You will then have access to the bottom. Take a brush that will fit through the opening, and loosen the rust.

After the rust has loosened a bit, you would have two options to remove the rust. The first option is to replace the valve and flush the tank continuously. The other option is to use a vacuum cleaner.

Draining And Flushing The Tank 

You would have to drain out the water from the tank to remove the rust from the bottom. The initial step for this method is to shut off the water heater.

Then, open a hot water faucet in the house and attach a drain hose to the drain outlet. Run the water in a buck or sink.

You will get rid of a lot of rust by continuously filling the tank with 3-5 gallons of water and letting the water drain.

Using A Wet-Dry Vacuum Cleaner 

Vacuuming the rust away is an efficient way to remove it. However, the vacuum hose should fit inside the drain opening. 

Using a 3/4 inch polybutylene can help reconfigure the vacuum hose to fit it inside the drain opening. To ensure thorough cleaning, brush after vacuuming and keep repeating it until you are satisfied with the result.

Be sure to replace the valve once done and wrap the threads using plumbing tape to ensure a tight seal.

Replacing The Sacrificial Anode

As mentioned earlier, a sacrificial anode is a long rod that prevents the walls of the water tank from corrosion. It is made up of a metal that corrodes faster than steel.

The sacrificial anode gets its name because it sacrifices itself by attracting corroding minerals from the water and sparing the water tank walls from rust.

It would be best to replace it periodically as it is designed to deteriorate. To do this, turn off the power and shut off the water.

Unscrew the sacrificial anode and lift it from the top of the tank. Then, replace it with another anode specifically designed for your water heater.

How To Change A Rusted Fitting In Water Heaters?

If you want to fix the problem yourself and change the fittings in your water heaters, here’s how you can do it. 

  1. Firstly, turn off the electricity to the water heater. Then, close the cold water inlet valve situated at the top of the water heater. 

Turn the hot water faucets on and let the water run until lukewarm.To ensure no more pressure in the tank, open the pressure relief valve.

  1. The next step is to remove the corroded fittings. There can be different kinds of fittings for different tanks.

The method to remove a union is to hold one side of it with a pipe wrench while turning the central knot with another pipe wrench. Fittings connected to copper pipes have to be cut off using a pipe cutter.

  1. Next, unscrew the nipples of the hot water tank with a pipe wrench and replace them with new ones. The new nipples should be of the same size as the previous ones. Use plumbing tape to wrap the nipple threads before screwing them into the tank.

Take a pair of dielectric unions and separate them. The galvanized half of each should be screwed to one of the nipples and tightened with a pipe wrench.

If you had to cut off the pipes earlier, attach a copper coupling onto each copper pipe. Screw the new fitting tightly above the water tank using pliers. Use Teflon tape to wrap the thread of the new fitting.

Slide a coupling to the end of the pipe that supplies cold water. The coupling must be aligned with the threaded fitting, straddling the joint. Adjust the coupling in place and turn the water heater back on.

What Effects Can Unfixed Water Heater Corrosion Have?

The consequences of unchecked corrosion in water heaters can be fatal. Depending on the leakage location, water pressure can affect the fixtures and appliances in your house, such as washing machines, dishwashers, faucets, etc.

In worse cases, the dissolved steel pipe threads can cause the pipe joint to weaken. As a result, the pipe joints can burst. It can cause immense damage to the house and plumbing infrastructure.


It is better to check the plumbing of your water heater from time to time to avoid corrosion. Frequent servicing will prevent your water heater pipes from rusting and causing your household appliances to malfunction. 

In most cases, you can fix problems related to corrosion yourself by using the methods mentioned in this article. However, certain circumstances require professionals to step in.

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