Water Quality FAQs: Appearance of water

Why is my water yellow?

When iron deposits become re-suspended, they can react with the oxygen in the water which can result in it becoming yellow in appearance, this is generally harmless. This discoloration can be caused by a disturbance in the main, such as a burst, or a cast iron pipe (typically used in the 1950’s and 1960’s) coming to the end of its life. In the case of the latter the yellow discoloration may also be accompanied by brown or black flecked particles. This may be as a result of a change in flow pressure (such as following a burst pipe or excessive supply demand) disturbing harmless deposits within the pipework.

If the water has a bright or fluorescent yellow colour, contact your water undertaker.


To improve this information please give us your feedback >
Your Feedback


Uncontrolled if downloaded. This is informative, non-statutory guidance and intended for general guidance purposes only; it is subject to change.

Compliance with this information should not be relied upon as guaranteeing no enforcement action will be taken by water undertakers. Water Regs UK accepts no liability for loss, indirect or consequential loss arising from or in connection with this guidance document.