Do Tankless Water Heaters Leak? Read This Before You Install One

Tankless water heating units are highly efficient and are equipped with advanced technology to provide hot water in very little time. They don’t have a storage tank. Water is heated on demand which means as you turn on the tap the water starts running through the pipes.

The heating elements then heat up this water. Due to no storage tank chances of leakage are less in a tankless water heating unit than in a tank one. Before buying a tankless water heater the consumers ask the question “Do Tankless Water Heaters Leak?”. Well,

After many years of use, however, some pipes or joints might start dripping water. These leaks might not cause any big issue in beginning but over time the leakage grows and can result in a catastrophic event.

The pipes often drip from the bottom. The best option in this scenario is to ask a professional plumber for help. They can help fix this issue and highlight the other complex issues with the unit if any present. Water leakage out of a tankless water heating unit can damage the floor, walls, and other appliances around.

The continuous leakage of water results in damage to expensive parts. To avoid this it’s better to check the problem in its initial stages and look for the right solution. Before looking for the long-term permanent solution to the issue try taking some prompt steps that will decrease the intensity of the damage.

One such immediate step can be to install a drain pan. A drain pan helps collect water from the leakage and convey it outside. This serves as a temporary solution for the clearance of the water that is leaking out of the unit. Continuous water leakage can be a source of mold growth or damaging the floors.

Both these issues are resolved once you use a drain pan. A drain pan helps control 100 percent of the leaking water. Using a drain pan is however a temporary solution and it won’t be helpful for the long term. If there is complete water failure then this solution is useless.

Causes of Tankless Water Heater Leakage

As we know like any other electronic equipment, a tankless water heater might also cause issues sometimes and one of them is leakage. Below we have briefly described the possible causes and solutions to fix the leakage of tankless water heaters.

Lack of Proper Venting

Tankless water heaters are either fueled by gas or electricity. These units have complex connections which means they are properly installed with proper knowledge or else it will result in leakage. Proper installation of the unit is a must condition for the right performance.

A proper vented unit prevents chances of leakage. If the ventilation is compromised the condensation can go into the unit and result in system failure.

An ideal venting should be short. A shorter venting means lesser cost alps lesser chances of leakage. The manufacturers provide an instruction manual that contains all the essential details for the functioning of a unit. It also lists the right steps to follow for the proper venting of the unit.

Gas Pipes

Gas tank-less water heaters are more efficient than electric ones. They have a higher water heating capacity. If the already gas connections present in your home are not enough to fulfill the needs of your water heating unit then try installing a separate gas pipe for the unit directly from the meter. Make sure there is a lesser number of joints in the pipe so the leakage chances can be minimized.

If you ever feel a weird smell around the unit apply a soapy solution on the gas pipe and look for any bubbles. If the bubbles form it means the pipes are leaking and it is an emergency for which you need to call in a professional plumber immediately. A gas leakage should never be taken lightly cause it can be fatal.

Water Pipes

When draining the unit for monthly maintenance you need to turn on the pressure relief valve. These valves are on the hot water out supply pipes. Some manufacturers supply a pressure relief valve with the unit while others are shipped without it. Ensure you get the required pressure relief valve for your tankless water heating unit cause it lessens the chances of leakage.

Hard Water

Water with a high level of mineral content is called hard water. These minerals can build up in the pipes and cause them to rust and corrode resulting in leakage. These minerals can even build upon the heat exchanger and will result in our supply of overheated water which can burn your skin.

Many tank-less water heating units have overheating protection features. The overheating due to build-up will result in automatic locking of the unit. An error code will be displayed on the control panel which you can easily understand by using the manual. There are specific models of tankless water heaters for hard water available on the market as well.

Trying to reset the system without solving the initial issue will result in again automatic shutting. This all happens to cause the main reason is not solved the unit is not able to function properly.

Trying to make the unit work without solving the root cause will result in permanent damage to the parts so you will need to replace them.

Acidic Water

Acidic water has a pH below 7. This sort of water can affect the pipes and create holes in them resulting in leakage. Check your water PH to make sure it’s within the normal range. If you find out that your input water supply is acidic then take steps to neutralize it. Neutralization is the only way to solve the problem and then you can use the same water supply for heating, bathing, cooking, and laundry.

High Flow Rates

All units need a certain range of water flow rates to function optimally. Tankless heating units need a low water flow rate and low input water pressure to provide the optimal performance level. With low flow rate units, it’s more convenient to correct the issues. If you own a tank-less water heating unit for residential use then a flow rate of 5 Gallon per minute is absolutely fine.

The right amount of pressure for a residential unit will be 30 psi. Check your water outlets regularly for any debris buildup. Make sure your showerheads are not clogged or the faucet aerator is working properly. If the water out supply is compromised it can result in a heater fire up.

How to Fix the Tankless Water Heating Leakage

Although rare if you face a scenario in which your tankless water heating unit is leaking there are some steps you can take to lessen the negative impacts of the solution and these are


Once you have sorted out the spot of leakage your next step depends on the magnitude of leakage. Get a professional plumber so they can fully inspect the unit and give a proper diagnosis of what went wrong. They will be better able to guide you about if you can repair the unit or it will end as a replacement.

Install a Drain Pan

Water leaking out of pipes will affect the floors and walls. If you want to avoid this from happening get a drain pan so that the water will be conveyed outside. Taking prompt action as soon as you notice a leak in your unit helps save the property. When you let the water leak for long it will cause mold growth on the floor. A drain pan will take away this water so your floors are tidy as before.

Contact Customer Service

Tankless water heating units are designed to last for a long and that’s why they have a long warranty. If your unit leaks while the warranty is still valid then call the manufacturer to ask for a replacement. The limit for a warranty on the heating element and other parts varies among different manufacturers.

Look for the warranty details of your particular model and make contact if you have a warranty. The warranty for a tankless water heater can be however voided if you installed the unit yourself and make some mistakes or the leakage was due to some mistake on your part.

Final Words

Always get help from a professional plumber for the installation of your tankless water heating unit. This minimizes any chances of leakage cause they know the right connections. Like all other appliances, your tankless water heating unit needs maintenance too. Make sure you clean the parts often and the input water supply is at the right temperature and pressure.

Getting service done by a professional once in a time increases chances of earlier detection of leakage and they can offer the right solution on time too. We hope that we have cleared your confusion about the question “Do Tankless Water Heaters Leak?”. If you have any more questions you can ask in the comment section.

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With years of experience under his belt, Adam decided to put his water heater knowledge to work. By providing high-quality content and expert guides, Adam hopes to help anyone looking for expert water heater advice.