Why Is My Tap Water Brown, Yellow or Orange?

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Do not drink discoloured water

Stop using the water for drinking and cooking until it runs completely clear. Do not run the hot tap — you risk contaminating your hot water cylinder.

What causes brown or yellow tap water?

Iron and manganese disturbed in water mains. Even treated water contains trace amounts of naturally occurring iron and manganese. Over time, these settle as deposits on the inside of water mains. When water flow changes direction — after a burst main, nearby maintenance, or a fire hydrant being operated — these deposits become disturbed and enter the supply. This is the most common cause.

Old iron or steel pipes. If only one tap or your hot water is affected, the issue may be corroding iron pipes within your own property rather than the mains supply.

Disturbed sediment in your internal tank. Some older properties have cold water storage tanks in the loft. Sediment can accumulate and be disturbed, particularly if the tank has not been serviced recently.

Is it dangerous?

Do not drink brown or discoloured water. Iron and manganese at these levels are not acutely toxic to healthy adults, but the water quality is compromised. Do not use it for:

Drinking or making hot drinks
Cooking
Infant formula
Filling aquariums or watering sensitive plants

What to do

1
Do not run the hot tap. Once discoloured water enters your hot cylinder, it takes much longer to clear. Cold tap only.
2
Check with neighbours. If they have the same problem, it is a mains supply issue — contact your water company.
3
Run the cold tap slowly for 15–20 minutes into a drain (not your garden or lawn — iron-rich water can stain). Do not flush the toilet or use appliances during this time.
4
If water clears, run it for a further 5 minutes then check with a white glass. When running clear, it is safe to use again.
5
If only your hot water is discoloured, this may indicate a problem with your cylinder or internal pipework — call a plumber.

When to contact your water company

Immediately, if you have not had recent plumbing work and neighbours are unaffected (may indicate an internal pipe problem they can advise on)
If neighbours are also affected — the company needs to know about the mains disturbance
If the water does not clear after running the cold tap for 30 minutes
If this happens repeatedly — it may indicate persistent iron pipe corrosion in the local network

Your water company is legally required to investigate water quality complaints and may arrange to flush the local main if iron deposits are the cause.

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Frequently asked questions

Is brown tap water dangerous to drink?

Do not drink discoloured water. Iron and manganese at these levels are not acutely toxic, but discoloured water indicates disturbed sediment or corroding pipes and should not be consumed. Do not use it for cooking, infant formula, or drinking until it runs clear.

Why has my water turned brown overnight?

This is usually caused by a burst main, nearby emergency repair work, or a change in water flow direction that has disturbed settled iron and manganese deposits in the water mains. It is a supply issue, not a problem with your property.

How long does it take for brown water to clear?

If it is a mains disturbance, the water usually clears within 15–30 minutes of running the cold tap slowly. If it persists beyond 30 minutes or neighbours are not affected, it may be a problem within your internal plumbing.

Should I run the tap if my water is brown?

Yes, run only the cold tap slowly. Running the hot tap first risks filling your hot water cylinder with discoloured water, which takes much longer to clear. Run cold only, slowly, for 15–20 minutes. If it does not clear, call your water company.

Why is my tap water brown, yellow or orange?

Do not drink discoloured water

What causes brown or yellow tap water?

Is it dangerous?

What to do

When to contact your water company