4 Common Causes of Water Heater Leaking and How to Fix Them

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As a homeowner, discovering your water heater leaking is a disconcerting and urgent situation. Addressing a leaking water heater quickly can not only save you from potential property damage but also from severe injury due to hot water hazards. Water heater leaks may manifest in various ways, including a small, nearly inconspicuous trail of water, or the sudden and relentless discharge of gallons of water. But what causes a leaky water heater? And more importantly, what steps can you take to fix this issue?

In this guide, we’ll explore the top four reasons why water heaters leak and provide detailed instructions on how to remedy each situation. At Maryland Sewer and Plumbing Service, our goal is to empower you with the knowledge to handle these issues safely and effectively. So let’s dive in and uncover the common causes behind water heater leaking that could impact your home.

Gray Water Heater in the Bathroom


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How Does a Water Heater Work?

Before we dive into the causes behind a water heater leak, it’s important to understand it’s basic functionality. Water heaters operate on a relatively simple principle, regardless of whether you have an electric water heater or gas water heater. At the core of the system lies a heavy-duty tank that’s insulated to keep water hot and ready for use. Cold water enters the tank through a dip tube and is heated by a dedicated heating element or a gas burner.

As the water heats, it rises to the top of the tank where it’s funneled through pipes whenever a hot water tap is turned on in the home, ensuring a consistent supply of hot water. Safety mechanisms, such as a pressure relief valve, are in place to prevent the tank from over-pressuring.

Importance of Addressing of Your Water Heater Leaking

A fully operational hot water heater transcends the mere luxury of contemporary living; it stands as an essential component of a hospitable and secure home environment. The ramifications of a malfunctioning water heater extend beyond the inconvenience of being without hot water. An escalating issue like hot water escaping from the unit has the potential to inflict serious burns or scalding injuries on unsuspecting individuals, especially young children and the elderly who are particularly vulnerable to such accidents.

Furthermore, the insidious nature of water damage stemming from a leak can have catastrophic effects on the structural integrity of your residence, compromise sensitive electrical systems, and ruin valuable personal items. This underscores the importance of swift and efficient management when faced with signs of leakage, to safeguard the well-being of household members and to protect the sanctity of your property’s framework and valued possessions. Immediate attention to any faults ensures the durability of the water heater, while also preserving the comfort and safety that a reliable hot water supply is meant to provide.

clear water droplet

Water Heater Leaking Cause 1: Pressure Relief Valve

The temperature and pressure relief (T&P) valve is a critical safety feature that keeps your water heater from exploding due to excessive internal pressure. It opens to release the pressure when the hot water tank gets too hot or the pressure reaches unsafe levels.

Troubleshooting Steps and Fixes

If you suspect a faulty T&P valve is the culprit of your water heater leak:

  • Shut off the power or gas to the heater.
  • Turn off the cold-water inlet to the heater to stop the leak temporarily.
  • Lift the T&P valve’s tab momentarily to ensure it isn’t stuck.
  • If water continues to flow, drain some water from the tank to clear out any debris.
  • If these steps don’t work, you may need to replace the T&P valve.

Replacing the T&P valve involves:

  • Installing a new valve that matches the old one in both pressure and temperature ratings.
  • Using thread-sealing tape or joint compound to create a watertight seal without over-tightening the connections.

Modern bathroom interior with white washbasin and tap under mirror reflecting water heater at home

Water Heater Leaking Cause 2: Loose or Damaged Drain Valve

A compromised drain valve can be identified by a consistent drip or stream of water, which may seem inconsequential but can accumulate to a considerable volume if not addressed. This valve, designed for periodic maintenance tasks such as draining sediment build-up from the tank’s interior, can loosen over time due to fluctuating temperatures and normal wear and tear. Regular checks are essential to catch and tighten a loose drain valve before it develops a leak.

In cases where the drain valve is damaged, perhaps due to corrosion, impact, or faulty components, it should be replaced promptly to prevent not only water loss but also potential damage to the surrounding area from uncontrolled leaks. Professional assessment is often recommended to ensure that the correct type of valve is used and that it is installed securely, maintaining the system’s integrity and performance.

Steps to Tighten or Replace the Valve

To address a hot water heater leak stemming from the drain valve:

  • Turn off the power or gas supply to the water heater.
  • Connect a garden hose to the valve, and place the other end in a floor drain or outside.
  • Open the valve to drain a few gallons of water and check for debris or damage.
  • If tightening the valve doesn’t solve the problem, a replacement may be necessary.

To replace the valve:

  • Drain the tank as much as possible.
  • Unscrew the old valve using a pipe wrench.
  • Wrap the threads of the new valve with thread-sealing tape and screw it in place, being careful not to over-tighten.

a rusted metal surface with blue paint on it

Water Heater Leaking Cause 3: Corrosion

Corrosion, or rust, is an electrochemical process that occurs on the metal surfaces of the water heater, particularly in environments where water quality is poor. It can compromise the tank, thermostat, and other vital components of your hot water heater.

Prevention and Repair Options

To prevent corrosion:

  • Regularly flush the tank to remove sediment.
  • Maintain the anode rod, which sacrifices itself to protect the tank from corrosion.
  • Install a water softener if you have hard water.

To repair corrosion:

  • If the tank is the source of the leak, the only solution is to replace the water heater.
  • For other components damaged by corrosion, consult with a professional plumber for appropriate replacement and repair options.

water drops on water base

Cause 4: Tank Leakage – The Most Severe of Water Heater Woes

Among the most severe issues a water heater can encounter is leakage directly from the tank itself, which frequently signifies an internal problem that can be traced to age-related deterioration or manufacturing flaws. Corrosion is a common culprit; over time, the natural reaction between steel and water can weaken the tank’s structure, leading to small fissures or holes. Additionally, a malfunctioning anode rod – designed to prevent corrosion by sacrificing itself – can lead to premature tank decay.

Manufacturing defects, though less common, can also compromise the integrity of the water heater tank. For instance, inadequate insulation or improper welding can lead to weak points that may eventually result in leaks. When such a leak occurs, it often signifies that the water heater has reached the end of its useful life and necessitates a full replacement rather than a repair.

Solutions Based on Severity

Different levels of tank leakage call for varying solutions:

For minor leaks:

  • Place a bucket under the leak to catch the water until you can address it long-term.

For moderate leaks:

  • Turn off the power and water supply to the heater and drain it.
  • Monitor the tank closely to prevent the leak from worsening until a plumber can inspect it.

For major leaks:

accidental physical damage, boiler cover, gas tankless water heater

Prevent Water Heater Leaking with Consistent Maintenance

The health of your water heater directly impacts the comfort and safety of your home. To ensure the longevity and efficient operation of your water heater, regular inspection and maintenance are key. Simple tasks like checking for leaks, testing safety valves, and flushing the tank can go a long way in preventing major problems.

Seek Professional Plumbing Help if Needed

While some water heater issues can be resolved with DIY techniques, it’s essential to recognize your limitations. If you are unsure about the cause of the leak or how to fix it, it’s best to contact a professional plumber. By doing so, you’ll not only gain the peace of mind that the issue is correctly resolved but also ensure that your safety and warranty are not compromised.

4 Common Causes of Water Heater Leaking and How to Fix Them Conclusion

Dealing with a leaking water heater can be stressful, but by understanding the causes and knowing how to respond, you can handle the situation with confidence. Regular maintenance and prompt action upon noticing a water heater leak can save you from significant headaches and expenses down the line.

Remember, as a homeowner, staying informed and taking proactive steps are your best defenses against unexpected water heater woes. Keep this guide handy, but more importantly, keep the contact information of Maryland Sewer and Plumbing Service at the ready. Your future self will thank you for the quick and informed action in the face of a water heater leak.

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