My water quality

What to do if your water looks unusual

If your water appears to be a different colour, looks like it might have bits in it, or seems cloudy, here’s what might be causing the change and how to fix it.

Why your water may appear to be a different colour

Water discolouration can vary from a straw-like yellow, to dark brown or black. There can be many reasons for this, including:

  • Disturbed sediment made up of naturally-occurring metals and minerals
  • Corrosion of pipes
  • Plumbing issues in your home

When your tap water is discoloured, you shouldn’t run the hot water tap, use dishwashers, washing machines or any other appliances which use your hot water supply.

Most discolouration can be quickly cleared by running the cold water tap nearest your internal stop-cock on a thin flow, about the width of a pencil, for 20 minutes. If this doesn't work, turn the tap off, wait 20 minutes and try again.

Although the water is discoloured, it should be fine to use to water any indoor or garden plants, so it’s worth collecting this in a washing up bowl or bucket while you run the tap so it’s not wasted.

If you’re on a water meter, we can credit your bill with an amount to compensate you for the water you’ve used to flush the system.


Discoloured water doesn't normally last for long and can often be cleared by running your cold water tap for five to ten minutes.

Select from the glasses below and find out more about why your water may be discoloured and what you can do:

If the discolouration doesn’t clear after running the tap for several minutes, check with your neighbours to see if their water is also discoloured.

If your neighbours’ water is also discoloured, it’s likely that it has been caused by a burst pipe or planned repairs to the network in your area.

What we’re doing to reduce discolouration

We have more than 90,000km of pipes and sewers, and we supply around 8 million people with clean drinking water every day. And we take away their waste too.

Our teams are working around the clock to make sure you get water that is some of the very safest on the planet.

We’re constantly carrying out proactive work to ensure you get the best possible service. This can include flushing sections of pipe to remove sediment and reduce the chances of discolouration occurring.

One of the main causes of discolouration is older iron pipes deteriorating with age. We’re working to replace these pipes in known discolouration hot spots, to eliminate
the root cause of many cases. We’ll always contact you to let you know when work like this is happening in your area.