The hot-versus-cold test
- Run cold only.Fill a clear glass from a cold tap and look and smell.
- Run hot only.Fill a second glass from the hot tap at the same fixture.
- Compare.If only the hot glass is discolored or smelly, the water heater is the likely source.
- Try another fixture.If one tap is bad and others are fine, look at that fixture's pipes or valve.
- Check the timing.Rust that clears after a minute may be from pipes; rust that stays may be from the tank.
What the clues point to
| What you see or smell | Hot only? | Likely source |
|---|---|---|
| Rusty, brown water | Yes | Corrosion inside the tank, often late in its life |
| Rusty, brown water | Hot and cold | Galvanized house pipes or a supply issue; check with the city's water utility |
| Rotten-egg smell in the water | Yes | Reaction between the anode rod and bacteria in the tank |
| White flakes or grit | Yes | Sediment from hard water, or a broken dip tube |
| Metallic taste | Hot and cold | Pipe corrosion; have the plumbing checked |
Rust and older Brea homes
Many Brea houses built in the 1950s through the 1970s were plumbed with galvanized steel or copper. Galvanized pipe rusts from the inside over decades, and that rust can show up in hot and cold water alike. When only the hot water is rusty, though, the tank is the stronger suspect: once its lining and anode can no longer protect the steel, corrosion inside the tank colors the water and usually comes before a leak.
A smell of sulfur in the hot water only is usually not a sign of danger to the house, but it is unpleasant. It comes from bacteria reacting with the anode rod. Plumbers often address it by flushing and disinfecting the tank or changing the anode type, depending on the manufacturer's guidance.
Next steps
- IfOnly hot water is rusty and the heater is olderThenAsk a plumber to check for tank corrosion and plan for replacement.
- IfHot and cold are both rustyThenHave the house piping checked, and contact the city's water utility if the problem is new and widespread.
- IfOnly hot water smells of sulfurThenAsk about flushing, disinfecting and the anode rod.
- IfThere is a gas smell in the airThenLeave and call 911 or SoCalGas from outside.
What to ask a plumber
- Is the rust coming from the tank or the pipes?
- What condition is the anode rod in?
- Would a different anode rod solve the smell, and does the manufacturer allow it?
- If the tank is corroding, how soon should I plan to replace it?
Common questions
Is rusty hot water dangerous?
It is mainly a sign of corrosion, either in the tank or in old pipes. It is worth having checked because tank corrosion usually leads to a leak.
Can I remove the anode rod to stop the smell?
Removing it leaves the tank unprotected and can void the warranty. Ask a plumber about the manufacturer-approved options instead.
Why does the smell only happen after vacation?
Water sitting unused in a warm tank gives bacteria time to react with the anode. Running and flushing the hot water often clears it.
General information for Brea, not a quote or professional advice. In an emergency, call 911.