Last updated: February 2024

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 >

Due to your Privacy Preferences, you'll need to enable reCaptcha cookies before completing this form.


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.

We use cookies to give you the best possible experience with Water Regs UK. Some are essential to provide website functions and ensure the website is secure. We also use cookies to help us understand how people use the site and to make improvements. Click "Accept All" to enable recommended settings or click "Manage cookies" to adjust your settings. For more details, see our Cookie Policy.