Last updated: February 2024

Water Quality FAQs: Appearance of water

Why does my water look cloudy?

There are normally two reasons why water may appear cloudy, both are usually harmless.

The most common reason is minute bubbles of air trapped in the water. These air bubbles are so small that they are not readily visible to the naked eye and customers often describe this as their water having a ‘white cloudy’, 'milky' or ‘chalky’ appearance.

Air bubbles in the water may be caused by for a number of reasons:

  • A loose or worn tap washer, this is usually accompanied by a distinctive ‘singing’ sound from the tap at certain flow rates.
  • A sudden reduction in pressure (because of opening the tap) which can release air dissolved in the water, in the same way as dissolved carbon dioxide is released when a bottle or can of fizzy drink is opened. This can be confirmed by filling a clear glass with water and checking to see if the cloudiness clears from the bottom to the top of the glass.
  • Maintenance work on your plumbing installation may cause air to become trapped within the system, especially if your water supply was turned off temporarily during the work.
  • If your hot water pipes run too close to your cold water pipes.

Another cause of white/cloudy water can be small particles in the water. These particles may have become dislodged from pipework or other water fittings within the property, becoming suspended in the water giving it a white cloudy/opaque appearance.When a glass is filled any such particles would slowly sink, leaving chalk like deposits at the bottom of the glass.

In both cases, leaving your taps running at a gentle steady flow for a short period should resolve these issues.



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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.

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