Water appearance

A yellow, brown, or orange colour in tap water is normally caused by disturbance of sediment (mostly iron particles) in the water main. This can happen after sudden changes in our network, like a burst water main or use of a hydrant by the Fire Service or another third party.

Check for any incidents or work going on in your area that could be disturbing sediment.

This is usually a short-lived problem that can be sorted out by flushing the discoloured water by running the tap. You should run the first mains-fed tap (usually in the kitchen) for 30 minutes to clear it. If the problem is more widespread, we’ll flush the mains by running lots of water through it.

We have an on-going programme of maintenance to reduce the amount of sediment in our network, through planned flushing and pipe replacement/upgrade. We’ll usually make you aware if we’re carrying out this work in your area.

The sediment will be mostly iron deposits from older cast iron pipes. Although the levels of iron aren’t likely to be harmful to health, discoloured water won’t look or taste very nice. We recommend waiting until the water runs clear again before using it for drinking and cooking.

If your tap water is persistently discoloured it might be being caused by the condition of your service pipe (the pipe that connects your home to the main) or your internal plumbing system. If your neighbour’s water is clear or if only your hot water is affected, it’s likely to be a plumbing problem.

Check the condition of any internal storage tanks and make sure the filling loop (used to top up water in the central heating system) is not left connected, as this can allow water in your radiators to mix with your tap water.

You may need a plumber to help you investigate - we recommend choosing a competent and qualified plumber using the WaterSafe scheme.

• Check the first mains-fed cold water tap (usually the kitchen cold water tap). If the water is clear, the problem is probably within your home plumbing system.
• Check with your neighbour. If their water is clear, the problem is likely to be either your plumbing system or your supply pipe.
• If your neighbour’s water is also discoloured there might be a burst water main locally or we may be flushing or carrying out other work in your area. 
• Try running the kitchen cold water tap at a steady flow until it clears. (This water doesn’t have to be wasted - keep it to water plants.)
• While the water is discoloured, we suggest you don’t do any laundry or use your hot water.
• If the water remains discoloured after several hours, please give us a call as we may need to investigate further or flush the water main.

Very brightly coloured tap water is likely to be caused by a problem in your plumbing system. The most common cause is water from a toilet cistern (containing a coloured disinfectant block) flowing backwards to mix with tap water (known as back-siphonage or backflow). The discoloured water may have a chemical or perfumed smell and form bubbles when shaken.

Very rarely, a bright blue or green discolouration to tap water is caused by high levels of copper from your household pipes. This could happen after new pipework is installed, or after a pipe is repaired or altered. Over time, new copper pipes form a protective layer that stops this from happening.

Sometimes bath water can appear to have a slight blue tinge. Very clear water will reflect blue light, which will be noticeable in a deep-filled white bath. You’ll probably find that the water looks clear if poured into a glass.

If the problem is water from the toilet cistern (containing a coloured disinfectant block) flowing backwards to mix with the tap water, you’ll need a plumber to install a backflow protection valve on the cistern or replace the existing one if it has failed.

If the discolouration is caused by high levels of copper leaching into water, running the tap should clear the discoloured water and reduce the level of copper. If this doesn’t work, please contact us for assistance.

It is not advisable to drink water that has an unusual, bright colour.

Cloudy water is usually caused by tiny air bubbles and is completely harmless.

Internal Plumbing Causes

If you have persistently cloudy water but your neighbours don’t, one of the following may be the cause:

• Warming of cold water pipe / Partially closed stop tap / Combi boiler

You may notice your water often looks cloudy first thing in the morning but clears after running the tap. This is due to warming of the cold water pipes in your home and can be especially noticeable in the winter. This is because the temperature difference between indoors and outdoors is at its greatest in winter. As cold water enters your home and warms up, dissolved air is released from the water, creating bubbles.

You can check this by watching how a glass of the cloudy water clears. If it’s air, the glass of water will clear from the bottom upwards as the air rises to escape from the surface.

Air may have become trapped in the water supply after work on our pipes, such as repairing a burst main. If there’s lots of air, it can make the water look white or milky. This usually clears within a few days. If it doesn’t, let us know as we may need to do some mains flushing to resolve it. You can check to see if we are carrying out works in your area.

Internal Plumbing Causes

Lagging your water pipes should help to minimise warming and transfer of heat. If your water is cloudy at all your taps, check that your internal stop taps are fully open. Partially closed valves can create turbulence in the plumbing system.

Combi boilers heat water very quickly, forming air bubbles with nowhere to escape. This can make your hot water look cloudy.

Yes, this is harmless.

White or pale-coloured bits or flakes: limescale

The water supply in this area is classed as hard or very hard because of the natural dissolved minerals in the water. Hard water forms limescale in and around taps, appliances and water fittings, especially where water is heated.

Limescale is usually white or pale yellow in colour, but it may also take on other colours from contact with metallic fittings or pipework, like green from copper or brown from iron.

Black bits

Some common causes of black particles in your water supply:

• Carbon filter media / Lead pipework / Tap washers / Mould and slime

Brown or orange particles

Tiny rust-coloured particles can sometimes appear in tap water after disturbance of sediment in older cast iron water mains. They can also come from older service pipes connecting homes to the mains network. 

If you have a water softener at home, the particles might have escaped from the unit. They might look like sand in your water supply but are actually tiny balls that are uniform in size and shape.

White or pale-coloured bits or flakes

You could try rinsing out or descaling your kettle. Make sure you rinse out any descaling product thoroughly before using your kettle again.

Sometimes limescale can detach from internal pipework and fittings to appear as bits or flakes in your water supply, for instance after operating a stop tap. Flushing your tap should help to clear it.

Some people choose to install a home treatment device to soften or condition their water supply.  

Black bits

• Carbon filter media

Sometimes carbon granules escape from home filters, like jug filters or plumbed-in units, appearing in water as tiny black particles. If you think this has happened, your filter should be checked or replaced.

• Lead pipework

Black bits or flakes can also come from older lead pipework, which might be present if your house was built before the 1970s. Lead is a health risk; exposure to lead from all sources should be minimised. Running your tap for a minute or so before taking water for drinking and cooking can help to reduce the level in your water supply, but the best way to reduce the risk is to replace lead pipework.

• Tap washers

Black bits or specks could also come from rubber tap washers or seals. This is particularly likely if only one tap in your home produces water with black bits. You may need to replace the problem tap or washer.

• Mould and slime

Biofilms can develop on damp surfaces. It can be black in colour and looks like black bits or slime when disturbed. Regular cleaning in and around tap spouts with a chlorine-based solution can help to minimise development. 

Brown or orange particles

If there is sediment in the water, then running your tap should help clear it.

If you think it’s coming from your water softener, contact your water softener provider for assistance.

White or pale-coloured bits or flakes

Hard water is not harmful to health. There is no maximum or minimum drinking water standard applicable to water hardness.

It is not caused by the quality of your water supply. These organisms thrive in warm, moist environments and are commonly found in bathrooms and kitchens in the home in places like:

• Shower heads and shower curtains / Tiles and tile grouting / Sealant / Plugholes and drains / Toilet cisterns and toilet bowls / Taps and inside tap spouts / Fridges and ice machines / Washing machines

The colour of slime will depend on the type and species of the organism – common colours are black, grey, green, or orange/pink.

Residues from some cosmetic and cleaning products can provide a nutrient source that encourages growth. Slime will also grow better on rough surfaces, especially on limescale deposits.

The following actions help to minimise the problem:

• Regular removal of slime and cleaning with a chlorine-based product. If slime is not removed regularly, it may form a permanent stain
• Better ventilation – open windows where possible and use extractor fans
• Rinse surfaces free of soap and shampoo
• Keep surfaces dry
• Remove limescale
• Regular cleaning of the inside and outside surfaces of taps with a chlorine-based disinfectant, including any tap inserts. Remember to run taps after cleaning to remove any remaining disinfectant
• Regularly run your washing machine and dishwasher on a hot service cycle and clean the seals and powder drawer

Hard water can leave white deposits or film on surfaces. Limescale is usually white or pale yellow in colour, but it may also take on other colours from contact with metal fittings or pipework, like blue/green from copper or brown from iron.