How to Repair Hot Water Heater Dripping: DIY Tips

It’s common for homeowners to wonder if it’s normal for their water heater to drip.

If you’re experiencing water heater dripping from the top or bottom during the unit’s recovery cycle or when hot and cold water aren’t in use, it could indicate a problem.

In this article, we’ll explore the possible causes of water heater dripping and provide solutions to fix it. By the end of this article, you’ll have a better understanding of what’s causing your water heater to drip and how to prevent further damage.

Water dripping from the faucet

What Causes Water Heater Dripping and What You Can Do About It?

Whether you have gas-powered or electric water heater, note that the puddle of water under the unit is often related to water leaking or water dripping such as condensation.

To troubleshoot the water heater dripping problem from the top and bottom, it’s essential to understand the function of various components such as the relief valve, expansion tank, drain valve, water outlets, anodes, and others.

We’ll explore how these elements are related to the dripping water issue and provide solutions to help address the problem.

Water Heater Is Dripping From the Top

The following elements located at the top of the water heater can be the source of dripping water:

Water Heater Is Dripping From the TPR Valve

TPR valve for a water heater
TPR valve (photo: amazon)

The temperature and pressure relief valve (TPR) is a safety feature designed to reduce the buildup of pressure inside the tank by releasing hot water. This pressure buildup occurs due to thermal expansion within the system, particularly when the temperature and pressure exceed the allowed levels.

The TPR valve is utilized to release this excess pressure, preventing the water heater tank and elements from experiencing excessive stress. Without proper pressure relief, various issues may arise, including creaking metal sounds, flue distortion, exhaust gas leaks, premature element failure, deformation, bulging, and even tank rupture.

Occasional water heater dripping from the TPR valve is the reason why you will see some wet spots on the floor and at the end of the discharge pipe.

What Happens During Thermal Expansion?

Thermal expansion, as previously explained, occurs when water is heated within a closed system, which includes one-way valves such as back-flow valves, pressure reducing valves, check valves, or even water softeners.

In this type of system, when water is heated, it expands and increases in volume, exerting pressure on the heater and plumbing system. Consequently, an expansion tank must be installed to accommodate the increased water volume.

How to Test a Water Heater for Thermal Expansion

expansion tank for water heating
Expansion tank (photo: amazon)

Before installing an expansion tank, it is important to confirm the thermal expansion in the water heater by performing the following test:

  • Reduce the temperature on the thermostat to its minimum.
  • Install the water pressure gauge on the drain valve.
  • Open the drain valve.
  • Open a hot water tap to release some water (up to 20% of the stored water).
  • Close the drain valve.
  • Ensure none of the fixtures are open.
  • Ensure there is no leaking on any of the taps or connections.
  • Increase the temperature on the thermostat so the unit can start heating water.

In a closed system, the pressure will begin to increase rapidly and steadily.

Once the pressure reaches the maximum value set on the TPR valve, the valve will open and release some water, causing a pressure drop. The valve will remain closed if the pressure inside the system does not exceed this value. However, if the pressure does exceed the set value, you will observe dripping.

Solutions for Thermal Expansion and Water Heater Dripping

One simple solution to address hot water dripping from the TPR valve or faucet is to install a pressure relief valve (PRV) and an expansion tank on the supply line.

The PRV valve is necessary to reduce the water pressure from the municipality pipeline system if it is excessively high. While the water heater operates with a maximum pressure between 40 and 60 psi, the incoming water pressure can reach up to 80 psi, requiring reduction.

The expansion tank is typically installed on the cold-water side of the incoming water pipe, positioned between the check valve and the water heater. It is designed as a small tank with two chambers: one side contains air under pressure, while the other side is filled with water and connected to the plumbing system, with a rubber diaphragm separating the two chambers.

The rubber diaphragm is capable of movement, adjusting to the inside pressure. When water pressure increases, the diaphragm moves towards the air chamber, compressing the air and accommodating the extra water volume, thereby reducing the pressure. For residential use, the device is designed to handle pressures up to 150 psi.

With these components installed, if you repeat the test mentioned earlier, you will observe a slight increase in pressure on the gauge, rather than a sharp and high increase. This pressure will be maintained throughout the heating process. The portion of water that expands and causes pressure will not exert any stress on the tank or elements, as it has been released into the expansion tank.

Water Heater Is Dripping From the Inlet/Outlet Pipes

Loose or damaged inlet/outlet pipes can be a common cause of water heater dripping from the top. The inlet and outlet pipes connect the water heater to the plumbing system of the home. Over time, the pipes may become loose due to wear and tear or from temperature changes causing the fittings to loosen.

Inlet/outlet pipes can also crack, corrode, or have faulty connections. In some cases, a loose pipe can also cause water hammer, a banging noise caused by the sudden stop of water flow, which can damage the pipes and cause water heater dripping.

To troubleshoot and fix inlet/outlet pipe issues, it’s important to turn off the water supply to the water heater and check the connections for leaks or damage. Tightening or replacing the fittings may resolve the problem.

Water Heater Is Dripping From the Anode Rod

An anode rod is an important component of a water heater that helps prevent corrosion of the tank. The rod is usually made of aluminum or magnesium and is designed to corrode instead of the steel tank. Over time, the anode rod can become corroded, reducing its effectiveness and leading to rust and corrosion on the tank.

If the anode rod is severely corroded, it can cause leaks at the top of the tank, resulting in water dripping from the top of the water heater. This is because the anode rod is located at the top of the tank, and when it’s corroded, it can allow water to seep through the tank.

To determine if the anode rod is the cause of the water heater dripping from the top, the anode rod should be checked regularly and replaced as needed. Typically, anode rods should be replaced every 3-5 years, depending on the water quality and usage.

Water Heater Is Dripping From the Bottom

Water heater dripping from the bottom, such as storage tanks, is usually a sign of a more serious problem that requires immediate attention.

Corroded Water Tank

The most common cause of water heater dripping from the bottom is a leak in the tank itself. Over time, the tank can rust and corrode, causing small holes to form.

When the tank develops a leak, water will begin to seep out from the bottom of the tank. In some cases, the leak may be small and go unnoticed for some time, but in other cases, it can cause significant water damage to the surrounding area.

Faulty Drain Valve

Another cause of water heater dripping from the bottom is a faulty drain valve. The drain valve is located at the bottom of the tank and is used to drain the tank for maintenance or repairs. If the valve is loose, damaged, or not closed tightly, it can cause water to leak out of the tank.

To fix a dripping drain valve, you can try tightening the valve with a wrench. If the valve is still leaking, you may need to replace it. To do this, turn off the power to the unit, turn off the water supply, and attach a hose to the valve to drain any remaining water from the tank. Then, remove the old valve and replace it with a new one.


To sum it up, a water heater dripping can be a sign of underlying issues that need to be addressed to prevent further damage and ensure safe operation. It’s crucial to identify the cause of the dripping, which could be anything from a malfunctioning pressure relief valve to a corroded anode rod or a loose inlet/outlet pipe.

Regular maintenance and inspections can help prevent water heater dripping, but if you do notice a problem, it’s best to consult a licensed plumber for assistance. Remember, taking care of your water heater is essential for both your safety and the longevity of the appliance.


What Is the Difference Between Leaking and Dripping?

Leaking and dripping are related but different concepts. Dripping refers to a slow, consistent flow of water, while leaking typically involves a faster, more significant flow of water. In the context of a hot water heater, dripping may refer to small drops of water falling from a specific area, such as the relief valve or drain valve, while leaking may indicate a larger flow of water from the bottom or sides of the tank.

Can a Dripping Hot Water Heater Be Dangerous?

Yes, if left unchecked, a dripping hot water heater can lead to damage or even failure of the unit. Additionally, it can increase the risk of flooding or other water damage to your home.

Can I Prevent Hot Water Heater Dripping?

While some causes of dripping may be outside of your control, regular maintenance and inspection can help prevent issues from arising. Additionally, installing an expansion tank and checking the pressure relief valve can help minimize the risk of dripping from thermal expansion.

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