What Causes Brown or Discolored Water from the Tap?

Turning on the faucet and seeing brown, yellow, or rust-colored water is alarming. In most cases it is not a health emergency, but it is a signal that something in your plumbing system needs attention. Here is what typically causes discolored water and what to do about it.

Rust in the Pipes

The most common cause of brown or orange water is rust. This happens when iron oxidizes inside your pipes or water heater. Older homes with galvanized steel pipes are especially prone to this - as the zinc coating wears away over decades, the steel beneath starts to corrode and flakes of rust enter the water supply.

If the discoloration appears only when you run hot water, the water heater is the likely source. If it affects both hot and cold, the issue is probably in the supply pipes themselves.

Disturbance in the Municipal Water Main

Sometimes the discoloration has nothing to do with your home's plumbing. When the city performs maintenance on water mains, opens fire hydrants, or increases water pressure suddenly, sediment that has settled in the pipes gets stirred up and temporarily enters household lines.

This type of discoloration usually clears on its own within a few hours. Run the cold water tap for several minutes. If it clears up, the source was likely the main line, not your plumbing.

Sediment Buildup in a Water Heater

Water heaters accumulate sediment over time, especially in areas with hard water. As minerals settle at the bottom of the tank, they can discolor the hot water coming out of your taps. If your water heater is more than seven to ten years old and has never been flushed, sediment is a likely culprit.

Flushing the tank annually is a standard maintenance step that removes this buildup. A plumber can do this during a routine service visit, or some homeowners handle it themselves with guidance from the manufacturer.

Well Water Issues

If your home is on a well rather than municipal water, brown water is often caused by iron, manganese, or tannins in the groundwater. Heavy rain or a drop in the water table can stir up sediment and temporarily affect water color. Well water problems tend to be more persistent than municipal ones and usually require testing to identify the specific cause.

How to Troubleshoot Discolored Water

Step 1: Identify which taps are affected. If only one faucet runs brown, the problem is localized to that fixture or the pipes immediately behind it. If all taps are affected, the issue is further upstream - either the main supply line or the water heater.

Step 2: Check hot vs. cold. Brown hot water only points to the water heater. Brown cold water only, or both, points to supply pipes or the municipal system.

Step 3: Run the tap for several minutes. If the water clears, the discoloration was temporary - likely a disturbance in the main line. If it stays brown, you have a persistent issue that needs investigation.

Step 4: Check with neighbors. If nearby homes on the same water system are also seeing discoloration, the cause is the municipal supply. Call your water utility's customer service line - they can usually confirm whether maintenance work is scheduled or in progress.

When to Call a Plumber

Call a plumber if the water stays brown after running the tap for five or more minutes, the problem keeps coming back, you also notice reduced water pressure or a metallic taste, or your pipes are older galvanized steel common in homes built before the 1970s.

A plumber can run a water test, inspect visible pipe sections, and check the water heater condition. If the pipes are the source, replacing a section or upgrading the full supply line may be the long-term fix.

Is Discolored Water Safe?

Temporarily discolored water from a main line disturbance is generally not a health hazard, but it is not something to ignore if it persists. Brown water caused by corroding galvanized pipes can carry elevated levels of iron and other minerals, depending on pipe age and condition.

If you are uncertain about safety, do not drink the water until you have had it tested or confirmed the source of the problem. Many municipalities offer free or low-cost water testing.

Bottom Line

Sources and editorial notes

Prices and permit requirements vary by location, property, equipment, and scope. Treat price ranges as planning estimates and confirm current requirements with the relevant authority and contractor.

• US Department of Energy - Energy Saver
• US Environmental Protection Agency - home, indoor air, and water guidance
• US Consumer Product Safety Commission - home safety

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• How Long Do Home Pipes Last? Signs It's Time to Repipe
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