Is Your Water Heater Leaking? Here’s What to Do

Edited: September 19, 2025

No matter where it comes from, a leak is never a good sign. When it’s your hot water heater, it usually means cold showers until the problem is fixed—and sometimes much bigger issues. If you’ve discovered your water heater leaking, here’s what you need to know and what to do next.

Is My Leaky Water Heater Dangerous?

This is one of the most common questions we hear from concerned homeowners. The short answer is yes—a leaking water heater can be dangerous if ignored.

The most immediate risk is water damage. A leaking tank can quickly flood surrounding areas, soaking into flooring and walls and creating the perfect environment for mold and mildew growth. This is especially concerning if your water heater is in an attic or second-floor utility space, since water can damage ceilings and rooms below.

In rare cases, a leaking water heater can also create a safety hazard. As water heats, pressure builds inside the tank. Normally, the temperature and pressure (T&P) relief valve safely releases that excess pressure. But if the valve is faulty—or if the system is neglected—pressure can build to dangerous levels. While actual tank explosions are extremely rare, the possibility exists when safety features fail.

The good news is that modern water heaters are designed with multiple safeguards, so the risk of explosion is very low as long as you don’t ignore warning signs.

What Causes a Water Heater to Leak?

Leaks can happen for a number of reasons, including:

• Corrosion and rust inside the tank that eat away at the metal over time.
• Loose or damaged connections where water lines attach at the top of the heater.
• A faulty T&P relief valve that no longer seals properly.
• Sediment buildup inside the tank that causes cracking or overheating.
• Age and wear—most standard water heaters last 8–10 years before replacement becomes necessary.

Leaks may also show up as discolored or rusty water from your hot taps, which is often a sign of tank corrosion even before you see pooling water.

Where Is the Leak Coming From?

The location of the leak often determines whether your water heater can be repaired or needs full replacement.

• Leaks from the top are usually connected to fittings, valves, or pipes. These can often be repaired without replacing the whole unit.
• Leaks from the bottom often mean the tank itself is compromised. If the tank is leaking, repair isn’t possible—you’ll need a replacement.
• Leaks from the drain pan (common in attic or garage installations) may indicate that the pan is doing its job but the tank has failed. If water is overflowing the pan, call for help immediately.

What Should I Do?

If you notice a leak, don’t panic—but act quickly to minimize damage. Here’s what to do before your plumber arrives:

1. Turn off the power to the water heater.

   • For an electric model: switch off the water heater breaker in your circuit panel.

   • For a natural gas model: turn the ON/OFF control knob on the tank to the OFF position.

2. Shut off the water supply.
   Locate the cold water shut-off valve above the water heater and turn it clockwise until it closes. This stops new water from entering the tank.

3. Call a professional plumber.
   A leaking water heater isn’t a DIY repair. Radiant plumbers can respond quickly, provide emergency service if needed, and help you decide whether repair or replacement is the safest option.

Preventing Future Water Heater Leaks

While some leaks are unavoidable due to age, regular maintenance goes a long way in extending the life of your water heater—whether it’s a traditional tank or a modern tankless system. Annual flushing helps prevent sediment buildup, inspections keep the temperature & pressure relief valve in check, and catching small issues early can save you from a costly replacement.

That’s exactly why so many homeowners join our Radiant Care Club. As a member, your water heater gets routine tune-ups along with the rest of your home’s plumbing and HVAC systems. Whether you own a tank model or tankless, our technicians make sure it’s running safely and efficiently year-round. It’s the simplest way to prevent unexpected leaks and enjoy peace of mind.

Austin & San Antonio Water Heater Experts

A leaking water heater is a serious issue that should be repaired or replaced right away. Luckily, Radiant technicians are specialists in all things plumbing and HVAC. That’s why we’re the trusted company for water heater repairs and replacements in and around the Austin & San Antonio metro area.

We’re proud to serve Austin, Round Rock, San Antonio, New Braunfels, San Marcos, and beyond. As Texas continues to grow, so does our service area—because serving our local communities is our top priority.