Why Your Hot Water Smells Like Rotten Eggs & How to Fix It

You hop in the shower, ready to relax, and suddenly—there it is. That unmistakable rotten egg smell. It’s one of those moments that makes you question everything about your plumbing. The good news? Your water heater isn’t cursed, and your pipes aren’t full of bad eggs. That sulfur-like stench is actually a pretty common issue in households and, thankfully, one that’s usually easy to diagnose and fix.

When your hot water smells like rotten eggs, it’s typically caused by bacteria reacting with minerals inside your water heater. The result? Hydrogen sulfide gas—that lovely “sulfur smell” you’re noticing. But before you panic or start Googling “top-rated Chula Vista water heater repair”, take a breath. There are a few reasons this happens, and several proven ways to eliminate it. Let’s break down what’s going on behind the stink and what you can do to make your water smell clean and fresh again.

What causes hot water to smell like rotten eggs?

If your water only smells when it’s hot, the problem is almost always linked to the water heater. Inside most heaters is a magnesium anode rod, which helps prevent corrosion by sacrificing itself to protect the tank. Unfortunately, when magnesium reacts with sulfur and naturally occurring bacteria, it produces hydrogen sulfide gas—the culprit behind that rotten egg odor.

You might also notice this smell if you’re using well water, since it tends to have higher sulfur and bacterial content than municipal water. These bacteria aren’t harmful, but they’re definitely unpleasant. In some cases, the odor can also appear if your heater’s temperature is too low, allowing bacteria to thrive.

If both hot and cold water smell bad, the issue might be coming from your water source instead of the heater. In that case, it’s worth testing your water for sulfur, iron, or other contaminants before moving forward.

How do I fix the bad smell coming from the hot water?

A quick test can help you figure out whether the smell is isolated to your heater or a broader water quality issue:

• Run cold water from a tap: If it smells fine, your heater is to blame.
• Run hot water only: If the rotten egg smell appears, you’ve found your culprit.
• Check other fixtures: If every tap in the house smells—even with cold water—it’s time to test your well or municipal supply.

How to fix the rotten egg smell?

That rotten egg smell isn’t just annoying—it’s your water heater’s way of asking for a little TLC. Whether it’s a quick flush, a new anode rod, or better water treatment, the fix is usually straightforward.

1. Flush & disinfect your water heater

Sediment and bacteria build up over time, especially in older tanks. Flushing your heater helps remove both.

• Turn off the power and water supply.
• Attach a hose to the drain valve and empty the tank.
• Refill it, then add a few pints of hydrogen peroxide (3%) and let it sit for two hours.
• Drain and refill again.

Hydrogen peroxide is effective because it kills odor-causing bacteria without damaging your tank.

2. Replace the anode rod

If flushing doesn’t solve it, your anode rod might be the problem. Consider replacing your magnesium rod with an aluminum-zinc alloy rod, which is much less likely to react with sulfur and produce that odor.

3. Increase the water temperature temporarily

Bacteria love warm, stagnant environments. Turning up your water heater to 140°F (60°C) for a few hours can help kill them off. Just make sure to warn everyone in your home so no one gets burned during this process.

4. Install a water filtration or treatment system

If your well water consistently tests high in sulfur or bacteria, you might need a whole-house filter, chlorination system, or aeration unit. These systems treat the water before it ever enters your heater, preventing future odor issues.

5. Schedule professional maintenance

Sometimes, the odor points to an underlying issue—like corrosion inside your tank or improper ventilation. A licensed plumber can inspect the unit, replace parts, and recommend preventive maintenance.

Which company in Chula Vista specializes in efficient water heater repair?

If you’re having trouble with your water heater, want to put in a newer model, or need any type of professional service, routine or emergency, Bob the Plumber is the name to call. We’re efficient, consistent, and committed to solving issues in the shortest amount of time with the least inconvenience possible to your daily routine.

Whether your water heater has suddenly stopped working, you want to learn the difference between gas and electric heaters, or you need help flushing your unit, we’re here and ready to help. Advice, guidance, or rapid response—our team will handle everything in a professional, thorough, and timely manner while you’re unwinding at Rohr Park. Don’t think of plumbers when it’s too late, preempt problems, call us today!