Brown or yellow tap water: what should you do?

Check the cold kitchen tap before guessing at the cause.

The answer in 2 lines. Brown or yellow water can come from disturbed deposits in the mains, a supply pipe or plumbing inside your home. Stop using it for drinking, cooking or making feeds while you seek advice. Compare the cold kitchen tap with other taps and ask whether neighbours are affected. Follow your water supplier's instructions about flushing and safe use. If only the hot water is affected, arrange a plumbing check rather than draining a hot-water cylinder yourself.

The first steps

Set aside discoloured water for drinking, food preparation and infant feeds until you have advice. Do not taste it to investigate.
Check whether the cold kitchen tap, other cold taps and hot taps are affected. Ask a neighbour whether they have the same problem.
Find your supplier on your bill or through Ofwat's contact directory. Open the relevant supplier's website and look for water quality incidents or report the change.

Stop: danger

Unusual colour together with an unusual smell, or blue, green or pink water: stop drinking it and contact your supplier promptly. Use the Drinking Water Inspectorate's brightly coloured water guidance to explain the symptoms; do not assume it is ordinary rust.
If a water-use restriction has been issued, follow its exact instructions. A notice to boil water and a notice not to drink it require different action.

What the pattern can tell you

These checks help you describe the problem; they cannot establish water safety or diagnose a particular component.

Cold water affected in neighbouring homes: a network incident is possible, especially after a burst or repairs. Ask your supplier whether the change matches a known incident.
Other taps affected but the cold kitchen tap clear: plumbing or storage within the property may need investigating.
Only hot water affected: tell the person responsible for your hot-water system. Do not assume the public supply is responsible.
A recurring problem after water has stood: record the pattern and ask for advice about the incoming pipe and internal installation.

Should you run the tap?

For ordinary brown, black or orange discolouration, the Drinking Water Inspectorate's guidance describes running the tap to help clear a recent incident. Read that guidance alongside the supplier's local instructions. Seek advice sooner if there is an unusual smell, another colour or any uncertainty about what has happened.

Use the incoming cold-water tap rather than flushing the problem through the hot-water system. Avoid leaving a tap running unattended or running every tap indefinitely. If it does not improve, tell the supplier what you tried and ask what to do next. Clear-looking water does not override an official restriction.

What not to do

Assuming that boiling makes discoloured water suitable for every use: follow the supplier's instructions about the specific incident.
Using the hot tap as an alternative drinking supply.
Opening a cylinder, tank or sealed heating appliance to investigate the colour yourself.
Assuming that a neighbour's clear water proves your own plumbing is safe.

White or cloudy water is a different check

Fill a clear glass from the cold tap and watch it stand. Cloudiness that clears from the bottom upwards is commonly caused by tiny air bubbles. Read the official cloudy-water explanation and compare the pattern. Contact the supplier if it fails to clear, recurs persistently or accompanies an unusual smell. This test explains likely air bubbles; it does not test for every contaminant.

For normal drinking and cooking, use the cold kitchen supply. The Inspectorate's taste and odour guidance explains why hot water and some stored bathroom supplies are unsuitable alternatives.

What to report, and who investigates

Keep photographs of water in a clear glass against a pale background. Note when it started, which taps are affected, whether it clears and whether neighbours have noticed it. Mention recent plumbing work or a supply interruption. Ask the supplier whether an investigation or sample is needed; do not assume a general area water-quality report explains a new incident.

If the supplier identifies a problem inside your home, arrange a qualified plumber. Tenants should send the evidence to their landlord or managing agent. Use GOV.UK's repairs guidance to check the landlord's responsibilities before commissioning work yourself.

Good to know

The Drinking Water Inspectorate covers England and Wales; Scotland and Northern Ireland have separate drinking-water regulatory arrangements. This guide concerns England.
A private water supply needs a different reporting route. Use the council finder, enter your postcode and ask the council's environmental health team about private water supplies.

Illustrative example: in Birmingham, Daniel notices yellow water after street repairs. His neighbour has the same problem. He sets aside the water for drinking, checks his supplier's incident advice and reports the affected taps. He follows the supplier's flushing and safe-use instructions rather than deciding that colour alone proves it harmless.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 4 November 2026, for England. Confidence: high for official water-quality advice and reporting routes; medium for possible causes, which require investigation. No chemical threshold or universal flushing duration is asserted.