Why is my tap water brown or discolored?

The EPA lists the culprits in its secondary drinking water standards, which are guidelines for how water looks, tastes and smells. They are not health limits, and the EPA does not enforce them. Two of them explain most brown water.

• Iron. The EPA's guideline is 0.3 milligrams per liter. Above that, iron can cause a rusty color, sediment, a metallic taste and reddish or orange staining.
• Manganese. The guideline is 0.05 milligrams per liter. Above that, manganese can give water a black to brown color and cause black staining.

The EPA also notes that corrosion of iron and copper pipes can stain fixtures and give water a red or blue-green color. So the color you see is a clue to the metal. Rust-orange and reddish points at iron. Blue-green staining points at copper. Dark brown to black can point at manganese.

Here is a useful fact for Phoenix homes. The city's 2025 water quality report lists iron in its water at "not detected" to 30 parts per billion, against a guideline of 300 parts per billion. In other words, the water leaving the city's system carries very little iron. When a Phoenix tap runs brown, the iron usually gets picked up somewhere along the way, either in the city's pipes during a disturbance or in the plumbing at your house.

The city's own guidance draws the same line. Phoenix says discoloration may come from aging pipes in your home or business, especially when it shows up on first use in the morning. It also says cloudy or discolored water may come from changes in the flow of the city's water lines. Recent crew work in your area or opened fire hydrants can stir up sediment. If the change is sudden, the city's lines are the likely cause.

### Four quick checks

You can sort out which one you have with a few quick checks. These are practical steps, not city rules.

1. 1Ask the neighbors. If the house next door has brown water at the same time, the cause is almost certainly outside your walls.
2. 2Try more than one faucet. If every faucet runs brown, look at the incoming water or the main line. If only one faucet does, the problem is likely in that branch or that fixture.
3. 3Check hot versus cold. Fill a clear glass from the cold tap, then from the hot tap. Brown only when hot points at your water heater, where sediment and rust collect at the bottom of the tank. Brown from both points at the supply or your pipes.
4. 4Note the timing. Brown water only at first use in the morning, clearing in a minute or so, is the classic sign of rust sitting in old pipes overnight. Phoenix mentions this pattern.

### When brown water points at your own plumbing

If the color keeps coming back, the cause is probably in your house.

• Galvanized steel pipe. Older homes with galvanized supply lines corrode from the inside, and the rust shows up as brown or orange water, low pressure and flaking. Our page on galvanized pipe problems explains what to look for and when replacement is the real fix.
• Old iron or corroded fittings. Rust from valves, fittings and older iron components can release color when water has sat or the flow changes.
• Water heater sediment. Brown hot water and clear cold water points at the tank. Draining and flushing the tank clears loose sediment, and our page on how often to flush a water heater in Phoenix gives a schedule. If the tank is old and the water is rusty, the tank itself may be corroding, and that is a replacement question.
• Hard water scale mixed with rust. Phoenix water is hard, and scale flakes mix with rust in older lines. Our guide to how hard water damages plumbing covers that side of it.

If lots of brown water arrives at first use each morning, and the plumbing is more than a few decades old, ask a licensed plumber to look at the supply lines. We can inspect the piping and give you an upfront price before any work starts. The estimate is free.

Start with the easy steps and work outward.

Run the cold water. Open one cold tap, ideally a bathtub or a hose bib, and let it flow. Tempe advises flushing the cold tap for one to two minutes when water has not been used for more than six hours, so that you draw water from the main rather than from your house plumbing. If the color clears quickly, you are done.

Wait if it is a city disturbance. If crews have been working nearby or hydrants were opened, the city says it may flush hydrants to clear the line, and clearing can take several hours. Waiting is fine. Avoid running the hot tap while the water is discolored, because that pulls the sediment into your water heater tank.

Hold off on laundry. Phoenix recommends not washing laundry while water is discolored. If you have to, use a rust stain remover or regular detergent, and skip chlorine bleach, since bleach reacts with iron to form a permanent stain. This one step saves people the most grief.

Know who should be careful. Phoenix says discolored water can generally be used for drinking, showering and flushing toilets. It also says people with severely compromised immune systems, infants and some older adults may be at increased risk, because cloudiness can interfere with disinfection and provide a medium for microbial growth. Those people should ask their health care provider about drinking the water. If you are in one of those groups, use bottled water until the water is clear.

The water in a toilet bowl shows color more than a glass does, because there is a lot of it and it sits. Three things usually explain it.

• The supply is discolored. If the tap water runs brown, the toilet tank fills with the same water. Flush the toilet a few times after the tap clears, and the color goes away.
• Iron staining in the bowl. The EPA says iron above its guideline leaves reddish or orange staining. A rust-colored ring at the waterline that returns after cleaning points to iron in the water or to hard water minerals.
• Something inside the tank. Older toilets with corroding metal parts can tint the tank water. If only the toilet shows the color, and sinks and showers are clear, the tank is the place to look.

To tell which one you have, lift the tank lid and look at the water in the tank. Brown water in the tank means the problem is the supply or the tank parts. A clean tank with a stained bowl points at staining, which a cleaner takes off. If it persists, our page on why tap water gets cloudy helps you rule out air and minerals first.

Call your water utility if the brown water shows up suddenly, lasts more than a few hours, or affects the neighbors. Phoenix Water Services lists 602-262-6251 on weekdays from 8 a.m. to 5 p.m., and 602-261-8000 on weekends, holidays and after 5 p.m. on weekdays. Other cities publish their own numbers on their water pages.

Call a plumber if:

• The color returns at every morning first use and the pipes are old.
• Only your hot water is brown, and flushing the water heater does not clear it.
• You see flakes or particles, or your water pressure is dropping along with the discoloration.
• Water is blue-green, which the EPA links to copper corrosion, or you smell something unusual.

Also call the utility right away if water looks oily, smells strongly of chemicals or is unusually cloudy and does not clear. Phoenix says that if drinking tap water is not advisable, its representatives visit the address, and on a large scale the media are notified and information is posted on phoenix.gov.

### Quick answers

Here are the short versions.

Is brown water safe to drink? Phoenix says discolored water can generally be used for drinking, showering and toilet flushing. It also advises that immune-compromised people, infants and some older adults ask a health care provider first.

How long does it take to clear? After hydrant flushing, Phoenix says it may take several hours. Rust from old pipes at first use in the morning often clears in a minute or so of running the cold tap.

Can I wash clothes? Phoenix says to hold off on laundry while the water is discolored, and never to use chlorine bleach on iron stains.

Do I need a filter? A sediment filter can catch rust particles, but it will not fix the corroding pipe that makes them. See our page on how often to change a whole-house water filter if you already have one.