Rusty Water From the Tap? What It Means and What to Do
By the Hot Water Heater Factory team · Updated October 2026
If only the hot water is rusty, the cause is almost always your water heater. If both hot and cold are rusty, look at your pipes or the city water main instead.
Step 1: hot, cold, or both?
- Only hot water is rusty: likely the water heater: a worn-out anode rod or a tank that's starting to rust inside.
- Both hot and cold: likely old galvanized pipes, or the city doing work on the water main nearby. City-related discoloration usually clears after running the cold tap for a few minutes.
Why water heaters make rusty water
Every tank has an anode rod, a metal rod that slowly corrodes so the tank doesn't. When the rod is used up, the steel tank starts to rust from the inside. Hard water speeds this up, which is why we see it often in the Inland Empire.
What can be done
- Younger tank, early signs: flushing the tank and replacing the anode rod can stop the problem and add years of life.
- Older tank, or rust with leaking: once the tank itself is rusting through, replacement is the only fix. A rusting tank will eventually leak.
A rotten-egg smell too?
A sulfur smell in the hot water usually comes from a reaction between the anode rod and bacteria in the tank. A different type of anode rod and a flush often solves it.
Seeing rusty water? Text us a photo of the water and your water heater's label. We'll tell you whether it's the water heater and what we'd recommend.