Why Is My Water Heater Making Rusty or Brown Water?

Brown or rust-colored water coming out of the tap is alarming, especially in the tub or a white sink. Sometimes it's a short-lived hiccup from the city's water mains. Other times it's a sign your water heater is corroding from the inside. A couple of simple checks will tell you which one you're dealing with.

First, figure out where it's coming from

Run the cold water at a faucet for a minute or two, then switch to hot at the same faucet.

• Only the hot water is brown: the source is almost certainly your water heater.

• Hot and cold are both brown: the problem is in your pipes or the water supply, not the heater.

• It happens at one fixture only: look at that fixture's supply lines or valve.

If both taps are brown and your neighbors are seeing the same thing, it's likely a water main issue. Hydrant flushing or a main break can stir up sediment. Run the cold water at your lowest faucet for several minutes and it should clear up. Avoid running hot water or doing laundry until it does, so you don't pull that sediment into your water heater or onto your clothes.

Why a water heater makes rusty water

The anode rod is used up

Every tank heater has an anode rod that corrodes on purpose so the steel tank doesn't. Hard water, like most of Hamilton County has, can wear it out faster. Once the rod is gone, the tank starts rusting instead, and that rust shows up in your hot water.

The tank itself is corroding

The inside of a steel tank is lined with a glass coating. Over time, small cracks in that lining expose bare steel. If the anode rod isn't protecting it, rust forms and flakes off into the water. The discoloration usually starts gradually and gets worse over weeks or months.

Sediment has built up

Mineral sediment mixed with rust can collect in the bottom of the tank. Stirred up by heavy hot water use, it can cloud or tint the water even before the tank is badly corroded.

When it's your pipes

If both hot and cold are discolored and the city isn't working on the mains, look at your plumbing. Many older homes in North Indianapolis, and some older homes around Carmel and Broad Ripple, still have galvanized steel water lines. Galvanized pipe rusts from the inside, and the rust breaks loose as brown water, low pressure or both. Well homes can also see orange or brown water from iron in the well water itself.

For galvanized lines, the long-term fix is replacing them with copper or PEX. For iron in well water, the answer is usually filtration.

How to fix rusty water from the heater

Flush the tank

Draining and flushing the tank clears out sediment and loose rust. If the water runs clear afterward and stays that way, the tank may still have good life left.

Replace the anode rod

If the tank lining is still mostly intact, a new anode rod can take back over the job of corroding and slow the rusting. This works best when caught early on a heater that isn't very old.

Replace the heater

If the rust comes back quickly after a flush, the tank is leaking, or the unit is near the end of its life, replacement is the lasting fix. A corroded tank can't be relined or patched. If that's where things stand, we'll show you what we found and explain why. We install Bradford White tank and Navien tankless heaters, handle the permit and haul away the old unit, and same-day replacement is often available. Right now you can take $50 off a tank installation or $500 off a tankless installation.

Keeping it from happening again

• Flush your tank heater once a year.

• Have the anode rod checked every few years, more often with hard water.

• Keep the temperature around 120°F. Hotter water speeds up corrosion.

• Make sure your water pressure isn't too high and your expansion tank is working.

• Consider a water softener to reduce mineral buildup in the tank and pipes.

When to call us

If hot water keeps coming out brown, or both hot and cold stay discolored after the city work is done, give us a call. We'll figure out whether it's the heater, the pipes or the water itself, then give you options and a price before any work starts. Learn more about water heater repair and replacement or whole-home repiping for older galvanized lines.

FAQ

Is rusty water safe to drink?

Small amounts of rust aren't considered a serious health risk, but it's not pleasant and can carry sediment. Use cold water that runs clear for drinking and cooking until the cause is found and fixed.

Can flushing the water heater fix brown water?

Sometimes. If sediment is the main problem, a flush can clear it up. If the water turns brown again within days, the tank is likely corroding and a new anode rod or a replacement heater is the better answer.

Will rusty water stain my laundry?

It can. Hold off on laundry until the water runs clear. If clothes do get stained, don't put them in the dryer, since heat can set rust stains.

Why is my hot water brown only after I've been away?

Water sitting in the tank gives rust and sediment time to settle and concentrate. Running the hot water for a few minutes may clear it. If it happens often, have the anode rod and tank checked.

Can a rusty water heater tank be repaired?

Parts like the anode rod, drain valve and relief valve can be replaced, but a tank that's rusting through can't be relined or patched. At that point, replacement is the safe choice.

Seeing brown water from your taps? Call or text (317) 731-3028, or visit our water heater service page.