Hot water comes out rusty or discolored

Symptoms

• Hot water runs rusty, brown, or orange, especially first thing in the morning
• Cold water from the same tap runs clear
• Problem is worse after the tank has sat unused for a while
• Sediment or rust flakes visible in a filled glass

Likely causes

• CommonCorroding water heater tank interiorOnce the tank's glass lining and anode rod are worn out, the steel shell itself starts to rust and shed particles into the water.
• CommonOld galvanized steel pipes corroding from the insideGalvanized pipe common in older homes rusts internally over decades, especially on the hot side which corrodes faster.
• PossibleDepleted anode rod no longer protecting the tankThe sacrificial anode rod normally corrodes instead of the tank, but once it's used up, the tank itself starts rusting.
• PossibleSediment buildup with a rust-colored tintSediment can pick up a rusty color from developing corrosion inside the tank without a full tank failure yet.

What to do

1. Fill a glass with cold water first to confirm whether discoloration is limited to the hot side.
2. Fill a glass with hot water from a tap closest to the water heater to minimize the effect of household piping.
3. If only hot water from taps far from the heater is rusty but water right at the tank is clear, suspect old galvanized pipe rather than the tank.
4. If hot water even close to the tank is rusty, have the anode rod inspected and consider replacement if it's still early enough in the tank's life.
5. Flush the tank to see if a one-time sediment issue clears up rather than ongoing corrosion.
6. If flushing doesn't help and the tank is many years old, treat continued rusty hot water as a sign the tank is failing.

Tools and parts

• Garden hose (for flushing)
• Clear glasses for testing

When to call a pro

If rusty water traces back to the tank itself rather than old pipes, and the tank is aging, a plumber can advise whether an anode rod swap will help or if replacement is the better path.

Safety