How to Fix Rusty Water From Your Hot Water Tap

If brown, rusty, or metallic-smelling water comes out of your hot tap, your water heater is almost always the source. Rusty hot water is a warning sign that something inside the tank is corroding. The good news: catching it early can mean a simple fix, while ignoring it usually ends in a leak and a flooded floor.

By Anthony Hamilton, Co-Founder, THE Water Heater Company (21+ years in water heaters). Reviewed by THE Water Heater Company's factory-trained technical team.

What causes rusty hot water

Rust in your hot water comes from three common sources inside a tank-style water heater:

• A depleted anode rod. Every tank has a sacrificial anode rod that corrodes on purpose so the steel tank doesn't. Once that rod is used up, the tank itself starts to rust.
• Tank corrosion. When the protective glass lining cracks and the anode is gone, the bare steel oxidizes and sheds rust into your hot water.
• Sediment buildup. Minerals settle at the bottom of the tank, trap heat, and accelerate corrosion. Hard-water areas across Southern California make this worse.

When it matters

Color tells the story. Slightly cloudy or rust-tinted water that clears after a minute may just be disturbed sediment. Persistent brown water, a rotten-egg smell, or rust that returns every time you run hot water means active corrosion is underway. The sooner you act, the more options you have.

Isolate hot-only vs. whole-house

This simple test points to the real problem:

• Run only the COLD tap. If the cold water is also rusty, the issue is your incoming supply or galvanized pipes — not the water heater.
• Run only the HOT tap. If only the hot side is rusty, the water heater tank is the culprit.
• Check a few fixtures throughout the home to confirm the pattern is consistent.

Hot-only rust isolates the problem squarely to the tank. Whole-house rust is a plumbing or supply issue that calls for a different repair.

Failure mode: what happens if you wait

Once a tank's anode rod is spent and the lining fails, corrosion only spreads. The metal thins from the inside until it perforates and leaks. A rusting tank cannot be reversed — the rust is structural damage to the steel. That's why rusty hot water is often the last warning before a tank gives out completely.

The fix — and when it means replacement

If the tank is relatively young and the only issue is a worn anode rod, replacing the rod can stop the corrosion and add years of life. Upgrading to a powered anode rod gives longer-lasting protection and can also cut down on the rotten-egg smell some homeowners notice. Flushing the tank clears sediment and helps it run efficiently.

But if the steel tank itself has begun to rust through, no anode rod or flush will save it. At that point, replacement is the only reliable fix. A water-heater specialist can tell the difference quickly by checking the tank's age, anode condition, and where the rust is coming from. We serve homeowners across Ventura, Los Angeles, and Orange County — see our service areas for your city.

Proof you can trust

THE Water Heater Company is a residential water-heater specialist — that's all we do. Our co-founders bring 42 years of combined water-heater experience, and we hold a 4.9-star rating across 2,100+ reviews with an A+ BBB rating. Our factory-trained technicians arrive in fully stocked trucks, so most diagnoses and repairs happen the same day.

Get rusty water diagnosed today

Rusty hot water won't fix itself. We offer same-day service, 7 days a week, so you can stop guessing and get an honest answer. Call (877) 798-7487 or book online and we'll find out whether it's a quick fix or time for a new tank.