Hot Water Heater Is Leaking? Here’s 5 Reasons Why
A leaking water heater might start as a small drip, but it can quickly turn into a major problem—causing water damage, mold growth, or even a total system failure. If you've noticed puddles near your tank or dampness around the base, don’t ignore it.
Whether you're in a cozy Chicago bungalow or a suburban home in Schaumburg, understanding why your hot water heater is leaking is the first step to solving the problem.
Let’s break down the five most common reasons — and what you can do about them.
1. Loose or Corroded Pipe Connections
The pipes bringing water into and out of your heater are under constant pressure. Over time, these connections can loosen, corrode, or degrade — especially if your heater has recently been serviced.
Quick Check:
- Look for moisture or rust near the pipe fittings.
- If it’s safe, you might try gently tightening them.
- But if there’s visible corrosion or water keeps leaking, it’s time to call a pro.
💡 Voice search tip: People often ask, “Why is my water heater leaking from the top?” — and this is usually the culprit.
2. Worn-Out Gaskets or Failed Thread Seals
If water is dripping around joints or seams, it could be due to worn-out gaskets or old thread sealant. These seals are meant to keep water tightly contained, but they can break down over time—especially on older units.
Incorrect installation or age can both lead to small, persistent leaks that get worse over time. A trained plumber can often replace the seals or fittings without needing a full unit replacement.
3. Faulty Drain Valve
Every water heater has a drain valve near the bottom, designed to empty the tank for maintenance or flushing. But if the valve is damaged, loose, or corroded, it can leak.
Symptoms to watch for:
- A slow, steady drip from the bottom of the tank
- A small stream of water (especially after maintenance)
- Mineral buildup or rust near the valve
If tightening the valve doesn’t stop the leak, it may need to be replaced.
4. Excessive Pressure Inside the Tank
When water heats up, it expands — which increases pressure inside the tank. Normally, your water heater’s pressure relief valve will release this safely. But if:
- The thermostat is set too high
- The valve is malfunctioning
- Or sediment has built up inside the tank…
…it can cause excess pressure, leading to leaks around fittings or valves.
Pro tip: If you notice short bursts of water from the pressure relief valve or hissing sounds, call a plumber immediately. This could be a warning sign of dangerous internal pressure buildup.
5. Internal Tank Corrosion or Cracks
Older tanks are especially prone to this. Over time, the protective anode rod inside your heater breaks down, allowing the tank itself to corrode. Eventually, this leads to internal leaks or even structural damage.
Unfortunately, once corrosion has compromised the tank walls, replacement is the safest and most cost-effective option.
Common signs include:
- Rust-colored water from hot taps
- A mysterious puddle with no visible leak point
- Sediment or metallic smells in your water
What Should You Do If Your Water Heater Is Leaking?
🧰 First: Turn off the power and water supply to your unit.
📸 Then: Take a quick photo of the leak (this helps when you call a plumber).
📞 Finally: Call a licensed professional like Quality Plumbing to inspect, diagnose, and recommend next steps.
Our team serves the northern Illinois area and has decades of experience working with both traditional and tankless units. We’ll help you understand your options—whether it’s a simple gasket swap or a full water heater replacement.
👨🔧 Need Help Today?
At Quality Plumbing, we take pride in offering honest recommendations, fast response times, and service that’s built to last. Don’t just take our word for it—read what your neighbors are saying about our work!