Where the color comes from

Water that looks yellow, orange or brown almost always carries iron. In an older building the most likely source is galvanized steel supply pipe whose inner coating has worn through, so rust flakes into the water, especially after it has sat in the pipe overnight or while the owner was away.

A tank water heater can produce the same look when sediment and rust collect at the bottom of the tank or when the tank itself begins to corrode. And sometimes the cause is outside the building entirely: work on a street main, a hydrant being flushed or a change in flow can stir up sediment that reaches every home on the block.

Narrowing down the source

Run a few simple comparisons and note what you see.

  • IfOnly the hot water is discoloredThenSuspect the water heater first; ask about flushing the tank and checking the tank and its connections.
  • IfCold water is discolored at the first draw, then clearsThenSuspect corroding galvanized pipe inside the building, where water sat overnight.
  • IfWater is discolored at every tap and neighbors report the sameThenContact the City of Fullerton's water utility; the cause may be in the public system.
  • IfOnly one fixture is affectedThenLook at that branch line and fixture; a single old section or valve may be shedding rust.
  • IfColor comes with low pressure or leaksThenPlan for a plumber to assess the supply piping, not just the water.

Sensible first steps

  1. Note the pattern

    Write down whether it is hot, cold or both, which taps, what time of day, and whether it clears after running.

  2. Avoid washing light laundry

    Iron-tinted water can stain fabric, so hold off on whites until it clears.

  3. Check with neighbors or the utility

    If others nearby are seeing the same thing, the city's water utility is the first call.

  4. Have the building's piping assessed

    If the problem is inside, a plumber can look at the water heater and the exposed supply pipe to find the source.

Quick facts

Most common indoor source
Corroding galvanized steel supply pipe
Second most common
Sediment or corrosion in a tank water heater
Outside source
Disturbance in public water mains
Who supplies the water
City of Fullerton water utility

Questions for the plumber

  1. Is the color coming from the supply pipe, the water heater or both?
  2. How old is the water heater, and is the tank itself rusting?
  3. Which sections of pipe are galvanized, and how corroded are they?
  4. Would replacing the water heater connections or one branch solve it, or is the pattern building-wide?

Common questions

Will running the tap fix rusty water?

If the color comes from water that sat in old pipe, running the cold tap for a while may clear it temporarily. It does not fix the corroding pipe, so the color usually returns.

Can a water softener or filter solve it?

Treatment equipment can change what comes out of the tap, but it does not stop galvanized pipe from corroding. Ask a plumber to assess the pipe before choosing equipment.

Does brown water mean the water heater is failing?

Not necessarily. Sediment can be flushed, but rust from a corroding tank is a sign it is nearing the end of its life. A plumber can tell the difference.

General information for Downtown Fullerton, not a quote or professional advice. In an emergency, call 911.