What Causes of Water Leakage in Tankless Water Heater? How to Fix?

After through a deep research we are tried to answer a million dollar question like; what causes of Water Leakage in Tankless Water Heater? How to Fix? Basically, Water leakage in tankless water heaters is rare. But the pipes and joints may start to leak because of long years of use. So there are some chances of leakage if it used for many years. We know, tankless water heaters do not store water in their unit as they heat water on demand. On the other hand, tank type water heaters are more likely to cause leakage in their system. They store the water in the tank and start the heating process. 

Any leakage should not be taken lightly by a user. They must try to solve the leaks and problems in the tankless water heaters. It is to be noted; tankless water heaters leak from the bottom part or along the connections. The user must be serious about the leak unless it turns out to be a big issue.

Water leakage is a sign of a big problem to come for a water heater. It is a direct signal for a user that the device needs to fix immediately. Careful users never take the issue lightly. They do a professional checkup to find the problems at the first stage. Manufacturer of the water heaters has many experts and professionals in their team. So you contact with an expert recommended by the manufacturer or a professional person to guide.

Continuous drops of water easily damage the floor, connections, walls, fittings, and roofs within days. Immediate action should e took for fixing the water leakage problem. Otherwise, small leakage will slowly but surely trigger to more significant issues. When small leakage issue s not handled, then it turns to a big point. Thus it becomes expensive to fix that issue. Many people later find it difficult to manage the cost. At last the unit becomes useless for use. When anyone detects any water leakage, quick action is to take.

People install drain pan as a temporary solution. They keep the pan for some time until leakage is decided to be solved permanently. The function of the drain pan is to act as a conveyor. It removes water without causing damage to floors, connections or walls. Leaked water eliminated to hundred percent due to the suitable drain pan. Quickly prevents the floors and walls from long term damage. The container is highly useful to save the cost of structural repairs. It also inhibits the mold growth.

Drain pan works for, but it becomes useless for the total failure of the water heater. The container is only a temporary solution.

What are the causes of water leakage in tankless water heaters?

The fundamental causes of leakage given below-

  • Improper venting is one the common cause of leakage.
  • Inefficient gas piping.
  • Faults in water pipe connections.
  • The system gets damage from a continuous flow of acidic and hard water.
  • The extremely high flow rate of water.

Venting issue

Venting made through a wall or roof. The function of a proper venting is to ensure that no condensation goes into the internal system of the water heater. You should try to make the vent short and small. Quick venting will help to minimize the occurrence of leakages. The pipe and connections are also becomes secured from leakages when the tankless water heater has vented in small form.

The unit requires proper installation. Most importantly, a user needs to follow the manufacturer’s instructions to start the process of venting. Many units face a problem because of improper venting which is a well-known culprit of leaking in tankless water heaters. The entire system is affected when the unit gets any leakage.

The function of proper gas piping

Tankless water heaters save energy. They have the efficiency to run in gas. In most cases, a separate gas line is necessary to run the water heater. Existing gas pipe may not supply the right amount of gas. Effective piping requires a new connection for the system to function. The pipeline did in the water heater from the meter. There is no need for any direct link from the entire primary source of the gas power. In the end, the joints get reduced after installation of the pipes with the gas connection. So there will be less chance of gas leakage from the unit.

Gas leakage is anticipated mainly by strong gaseous smell. Then you confirm it by applying soapy water in the suspicious areas. It will show the gas upfront in a foggy manner. When you find a gas leak in your home, it is an emergency incident. Licensed experts must handle the whole unit.

Water pipe connection and relief valve

Relief valve reduces water leakage through joints. The water heaters come with relief valves nowadays. It usually located on the outlet part of the hot water. Outlet connects with the pipe leaving the heater to fixture. The valves are required to flush or drain the tankless system. Union connections of a relief valve are smooth and do speedy replacements. The user should get a kit with appropriate relief valve measuring its heater size.

Effects of hard water

Hard water builds up a layer of dissolved particles in the pipe after a certain period. It affects the piping system enormously. People are always concern about the hard water issue. Particles of hard water affect the heat exchanger which causes overheating of the unit. Many internal and external systems get affected by this particular problem.

The system signaled error code when a massive amount of water particles began to build up. The total system automatically gets locked. A user should solve the problem first about the hard water. People need to correct the error, and it will not shut down. If someone reset the tankless water heater without correcting the error, it will again stop functioning because the problem has not solved yet. You cannot force the system to work. It leads to system failure. In each case, proper diagnosis and fix of the issue is a must for a water heater.

Acidic water and water PH level

Metals of the unit and pipes are profoundly affected by acidic water. From time to time the acidic water makes the unit weak. It develops different issues like pinholes in the water heater. Pinholes create leakage problem after a particular time. Water PH level information is required to determine how fast the acidic water will create significant damage in the tankless water heater. Experts always suggest checking the acidity level in your region and country state. Therefore by checking the PH level of water, you can take action for minimizing the chance of damage in your unit. You also neutralize the issue by analyzing the information when you find the level of PH is not good enough for your system.

The extreme Flow rate and water pressure

Low water pressure with flow rate is always good. It is suitable to run a tankless unit for a very long time. It makes a massive impact on your system. To use the residential appliances, the ideal flow rate is 5 GPM having a steady pressure of 30 PSI. The problems are solved easily having a low flow rate. But it becomes tough to resolve an issue when the area has a high flow rate. The heater gets burned if there is debris in showerhead or aerators near the faucet. Careful users do regularly checking to be safe all the time.

How to fix?

Due to various reasons, tankless water heaters get into leakage issue. The necessary remedies to ensured by a user shown below-

  • Decide to do repair or replacement following the advice of a professional plumber.
  • You are installing drain pan. Drain pan mitigates leaking hazards.
  • Replacement from the manufacturer.
  • Warranty support from the manufacturer.

Checking the system for repair or replacement

Quick action will help to recover the leakage. When you have realized your tankless water heater is leaking take fast action to solve right at the moment. The user needs to find the leakage to take corrective action. The system is to be checked by a professional plumber for providing the right diagnosis. An expert plumber will help you by suggesting whether to repair or replace the unit.

Mitigate leakage by the drain pan

Precaution from leakage is not an easy task. A user has to be patient about it. At first, follow some fundamental ways to prepare for leakage if it happens. It will be helpful for you to keep your property safe in the house. Installation of a drain pan is one of the common ways to lessen the hazard of leakage. Drain pan minimizes damage. If you do not use drain pan, it will affect your property because leakage makes the water flow into your house. As a result drain pan is to consider in the first step.

Warranty and replacement support

Warranty offered on the heat exchanger and some other parts of the water heater. The support is provided to solve the user's issue against the eater. When the water heater starts to leak before the expiry date of the warranty you are bound to contact the manufacturer. The manufacturer will provide the help for replacement. Warranties offered are half of the life expectancy. People should know the terms and conditions of the support. Otherwise, the manufacturer can invalidate the warranty if the users carelessly use the unit.


Tankless water heaters need proper maintenance. From time to time regular servicing of the unit is also essential. If the unit used carefully, then occasional servicing is enough. You make sure professional plumber analyze your unit when you find any issue. Thus it will help to detect any leakages earlier. You can have the counteractive solutions in place right at the moment.

The manufacturers always tell the users to install the unit by a licensed contractor. So you should let a licensed contractor do the installation and service it when needed. The warranty support will not be invalid. You will get support from the manufacturer and professional experts.

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