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Fix a water heater that produces rusty water

We'll confirm the source is the water heater, replace the anode rod, flush the tank, or tell you when to call a pro.

Troubleshooting · Home plumbing
30–90 min
What you'll need
  • Breaker bar and socket (for anode rod)
  • Hose for draining
  • Replacement anode rod (matched to your tank size and water type)
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Steps

Goal: Confirm the source is the water heater, then replace the anode rod, flush the tank, or call a pro.

  • Run cold water from a few fixtures—if cold is clear, the problem is the water heater.
  • Good: Cold clear, hot rusty. Proceed to Replace anode rod.
  • Bad: Cold also rusty—source is elsewhere. See When to get help.

Confirm source

Goal: Verify the rusty water comes from the water heater, not the pipes or main.

  • Run cold water from several fixtures. Then run hot water.
  • Good: Cold clear, hot rusty—water heater is the source. Proceed to Replace anode rod.
  • Bad: Cold also rusty—check pipes or call a plumber.

Replace anode rod

Goal: Replace the anode rod if it is depleted—it protects the tank from rust.

  • Shut off water and power or gas. Drain a few gallons. Locate the anode rod on top of the tank (often under a plastic cap).
  • Use a breaker bar and socket to unscrew it—the tank may need to be braced. Install a new anode matched to your tank size and water type. Refill and restore power or gas.
  • Good: New anode installed. Flush the tank to remove sediment. Test the water.
  • Bad: Anode is stuck or you cannot remove it—call a plumber.

Flush tank

Goal: Remove sediment that can discolor water.

  • Attach a hose to the drain valve, run it to a drain. Open the valve and drain several gallons. Open a hot faucet to break vacuum. When the water runs clear, close the drain and refill. Restore power or gas.
  • Good: Clearer water after flushing.
  • Bad: Still rusty—replace the anode rod or call a pro if the tank may be corroding.

When to get help

If rusty water returns quickly after replacing the anode and flushing, the tank may be corroding from the inside. A plumber can assess and recommend replacement.

If you see rust on the outside of the tank, leaks, or the tank is over 15 years old with persistent rusty water, call a plumber.

Verification

  • Hot water flows clear at the fixtures.
  • No rusty discoloration when you first run hot water.
  • The anode rod is replaced and the tank has been flushed.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm source Verify rusty water is hot-side only—cold clear means water heater is the source.
  2. Replace anode rod Replace the anode rod if it is heavily corroded.
  3. Flush tank Drain and flush the tank to remove sediment.
  4. Test Run hot water and check for improvement.
  5. Call a pro Rusty water returns quickly, tank leaking, or rust on outside—call a plumber.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Whether cold water is also rusty
  • Water heater age
  • Anode rod condition
  • Steps already tried

Is the rusty water only from the hot side?

If cold water is also rusty, the source is pipes or the main supply, not the water heater.

Run cold water from a few fixtures. Then run hot. Good: cold clear, hot rusty—water heater is the source. Bad: cold also rusty—source is elsewhere; check pipes or call a plumber.

Yes No

You can change your answer later.

Is the anode rod heavily corroded?

The anode rod protects the tank. A depleted rod allows the tank to rust.

Shut off water and power or gas. Drain a few gallons. Locate the anode rod on top of the tank. Inspect it—if more than 6 inches is corroded or it is soft, replace it. Good: rod is depleted—replace it. Bad: rod looks good—try flushing first.

Yes No

You can change your answer later.

Replace anode rod

Replace the anode rod with a matching part. Refill the tank, restore power or gas. Flush the tank to remove sediment. Test the water. If rusty water returns quickly, the tank may be corroding—call a pro.

Done

Flush the tank

Attach a hose to the drain valve, run to a drain. Open the valve and drain several gallons. Open a hot faucet to break vacuum. When water runs clear, close the drain and refill. Restore power or gas. Test. If still rusty, replace the anode rod or call a pro.

Done

Call a pro

If cold water is also rusty, the source is pipes or main—call a plumber. If rusty water returns quickly after replacing the anode and flushing, the tank may have tank corrosion—call a plumber to assess replacement. If you see rust on the outside of the tank or leaks, call a plumber.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a water heater produce rusty water?
Common causes: a depleted or corroded anode rod (no longer protecting the tank), sediment buildup in the tank, or internal tank corrosion. Replace the anode rod and flush the tank first. If the tank is corroding, it may need replacement.
Can I fix rusty water from a water heater myself?
Yes. Replace the anode rod if it is heavily corroded. Flush the tank to remove sediment. If the tank is severely corroded inside, flushing may help temporarily, but the tank will likely need replacement—call a plumber.
When should I call a plumber for rusty water?
If the anode rod is replaced and the tank is flushed but rusty water returns quickly, the tank may be corroding from the inside. A plumber can assess whether the tank needs replacement. If you see rust on the outside of the tank or leaks, call a plumber.

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