Why is only my hot water brown or discolored?

Start with two clear glasses at the same sink. Fill one from the cold side and one from the hot side, and hold them up to a window. Then do the same at a second sink in another part of the house.

• Hot brown, cold clear, at every sink. The water heater. Keep reading.
• Hot and cold both brown. The supply or your pipes. Our page on why tap water turns brown covers that case.
• Brown at one faucet only. The pipe or fixture feeding that faucet.
• Brown mostly first thing in the morning, then clearing. The City of Phoenix FAQ says discoloration may come from aging pipes in a home, especially if it shows up on first use in the morning.

### Did the city just work on your street?

Timing matters. The Phoenix FAQ says cloudy or discolored water can follow changes in flow in the city's lines, such as when crews have been working in the area or fire hydrants have been opened. It says visible particles are generally iron or minerals that were stirred up, and that the city's lines are the likely cause when the change happens suddenly.

Here's how that can leave only your hot water brown later. The cold taps clear once the main settles. But any discolored water that flowed into the water heater while you were using hot water can leave its particles in the tank. So the cold side looks fine a day later, and the hot side keeps coming out tinted. If that's your timeline, a tank flush often clears it.

A standard tank heater, like the A. O. Smith model in the manual cited here, is a steel tank with a glass lining. Two things inside it can color the water.

### A used-up anode and a rusting tank

Every glass-lined tank has at least one anode rod, a metal rod that corrodes on purpose so the tank doesn't. A. O. Smith's manual explains it: the anode slowly wears away and protects the glass-lined tank from corrosion. Then it says the part that matters here: "Once the anode rod is depleted, the tank will start to corrode, eventually developing a leak."

That rust is what turns the hot water brown or orange. Rheem says rust-tinted or cloudy water points to corrosion or high mineral content inside the tank or pipes, and that flushing the system and checking the anode rod can prevent more serious damage.

A. O. Smith lists what makes anodes wear out faster: poor water quality, hotter water settings, heavy hot water use and water softening. It says artificially softened water is exceedingly corrosive and that a softener may shorten the life of the tank. It recommends inspecting the anode after no more than three years, then every year after that. Our page on whether a water softener can damage a water heater goes deeper on that trade-off.

### Sediment and iron in the bottom of the tank

The second cause is simpler. Minerals and iron that come in with the water can settle in the bottom of the tank. Phoenix's 2025 Water Quality Report lists total hardness of 10 to 17.6 grains per gallon, so there is plenty of mineral in the water to begin with. Stir up that layer with a big draw and some of it can come out at the tap.

Pay attention to the pattern before you call. Note whether the color shows up only at the start of a big draw, like filling a tub, or every time you run hot water, and whether it has been getting worse. That tells a technician a lot. Our page on sand or grit in hot water covers the grainy version of this, including the broken dip tube case.

### Could it be the hot water pipes?

Sometimes. The Phoenix FAQ says aging pipes in a home can discolor water. If one bathroom's hot tap is much worse than the rest, the pipe run to that bathroom deserves a look. Our page on galvanized pipe problems explains what older steel supply pipes do as they age. A blue or green tint on the hot side is a different story: see the next section.

For washing, mostly yes. For drinking, you shouldn't drink from the hot tap anyway.

The EPA lists iron among its secondary drinking water standards and says iron above that guideline causes rusty color, sediment, a metallic taste and reddish or orange staining. EPA sets secondary standards for taste, color and odor, and says they are not considered a health risk at those levels. The Phoenix FAQ says discolored water can generally be used for drinking, showering and cleaning. It says that when water is discolored, you should either skip laundry or use a rust stain remover or regular detergent, but not chlorine bleach, because bleach reacts with iron and can form a permanent stain.

The bigger rule is about the hot tap itself. The Minnesota Department of Health says to use cold water for drinking, cooking and making baby formula, because hot water releases more copper from pipes than cold water. Phoenix's 2025 Water Quality Report gives the same advice to use only cold water for drinking, cooking and making baby formula as a lead precaution. That holds whether your hot water is brown or crystal clear.

If the hot water has a blue or green tint, or leaves blue-green stains, that points to copper rather than rust. MDH says blue-green stains on fixtures and pinhole leaks can be signs of corrosive water, and that water with a lot of dissolved copper can taste or smell bad or look blue. Our page on pinhole leaks in copper pipes covers that problem.

Work through it in order.

1. 1Flush the tank. If sediment is the cause, a flush can clear it. Rheem lists flushing as a job most homeowners can handle safely. Our page on how often to flush a water heater in Phoenix has the schedule and steps.
2. 2Check the anode. Rheem says to replace the anode if it's worn or mostly coated with calcium, and that checking it every year can add years to a heater's life. It also says anode work often needs tools and safety steps best handled by a qualified plumber. A. O. Smith notes that a special anode rod may be available if water odor or discoloration occurs.
3. 3Look at the tank's age and condition. If the water is still rusty after a flush, the anode is gone and the tank is old, the lining is likely rusting. That doesn't get better.

A. O. Smith warns never to remove the anode and leave the tank unprotected. It says doing so voids the tank warranty.

### Signs it's time to replace

Rusty hot water plus any of these points toward a new heater: water around the base, rust on the tank fittings, a heater near the end of its expected life, or a pop and rumble that a flush didn't fix. Our pages on a water heater leaking from the bottom and whether to repair or replace a water heater cover those calls. Catching it before a leak lets you plan the swap on your schedule, not in a flooded garage.

We'll run the hot and cold test with you, drain a sample from the tank, and check the anode, so you know whether you're looking at sediment, a worn rod or a rusting tank. If a flush and a new anode will do it, that's what we'll recommend. If the tank is done, we'll quote the replacement up front. HQ Plumbing and Air handles water heater repair and replacement, is licensed and insured, takes calls 24/7, and gives free estimates.