Services » Environment & Recreation

Discoloured Water

Drinking water supplied by Cork City Council to your tap will normally look clear and bright with no visible particles.  On rare occasions it might appear yellow, orange, brown, cloudy or black. 

Discoloured water is usually due to the disturbance of rust deposits formed by corrosion in the water pipe.  Drinking water may contain higher levels of naturally occurring iron or manganese which may result in settlement within water mains.  Under normal circumstances these settled deposits have no effect on water quality but when unavoidable changes are made to the direction of flow or when essential maintenance work is being carried out they can be re-suspended to cause


Re-suspension may also occur when a water mains bursts, during operational activities, excessive customer demand or when there is a sudden increase in water use e.g. for fire fighting purposes.  Discolouration can also be due to the condition of the pipe network or even the condition of the plumbing within your house.

Whilst discoloured water caused by iron and manganese deposits is unlikely to be harmful to your health, it is sensible not to use discoloured water to make up infant feeds or babies’ bottles.

Discoloured water can cause a considerable nuisance as it can affect the colour and taste of water. Please check the clarity of your water at the kitchen tap before use particularly when operating drink vending machines, dishwashers and washing machines as on some occasions, the iron may discolour laundry.  If this happens firstly check that your mains water is clear then re – wash your clothes after following a few simple tips:-


  • Keep the clothes damp and run the tap until the water runs clear

  • Use a synthetic detergent rather than a natural soap

  • Do not add bleach


Sometimes, discolouration may continue at properties located near the extremities of the water distribution network in which case we ask customers to contact us so that we can arrange for the water main to be flushed through to restore a clear supply of drinking water.

Discolouration usually clears fairly quickly after a few minutes of flushing the tap, but if you are concerned or the problem persists and does not clear after approximately 45 minutes of flushing, please contact the Water Services Section on 021/4924514 or 021/4924228


Please check to see if your neighbour has the same problem before contacting us.