Chemicals

Some plumbing materials that come into contact with the water supply in homes, offices and factories can give water unpleasant tastes and odours. When water comes into contact with plastic or rubber pipes or fittings, small amounts of substances may dissolve into the water. 

Sometimes, chemical tastes and smells can be irregular, this could be due to:

• Changes to water pressure – at night the pressure of your water supply may be slightly higher as less people are using it, which can cause a slight expansion in any rubber hoses you may have attaching your washing machine or dishwasher to the supply. When a tap in your property is used in the morning, the pressure reduces again and the expanded rubber pipe collapses, squirting water into the incoming water.
  
  
• Deterioration of washers – this happens over time, but as this is not a continuous process, the taste can come and go at times.

These kind of tastes and smells may be caused by the common household causes below:

• Standing water in pipes for several hours or more is more likely to be affected by the materials of your pipework.
  
  
• Rubber and plastic hoses connected to washing machines and dishwashers can cause chemical, rubber, plastic or ‘TCP-type’ tastes or smells to your water if they are plumbed into pipework before your taps.
  
  
• Rubber materials in fittings such as taps, or pipes used to fill drinking water tanks may also impart a taste to the water.
  
  
• If you notice a taste only in hot drinks, it may be due to seals in your kettle. This may be more noticeable with newer kettles – rinse these well before using them.
  
  
• Backflow from boilers can also lead to unusual chemical tastes. Check to see if this may be applicable to your boiler, you may need a plumber to look at this for you. Need a plumber?

• If it’s first thing in the morning or water has been standing in your pipes for several hours or more, try filling a washing-up bowl with water to draw fresh water through the pipe – why not use the water in the bowl for watering plants? You should notice a slight change in the temperature of your water when all of the water has been cleared from your system.
  
  
• If you have a washing machine or dishwasher plumbed into pipework under the sink, try closing the valves and seeing whether the problem persists. If this resolves the problem, you may need to fit a one-way check valve between these and your tap. 
  
  
• Ensure that all your fittings are Water Regs UK approved, which are tested to ensure that they do not cause taste, smells or encourage bacterial growth.
  
  
• If you notice a taste only in hot drinks, seals in your kettle could be causing the issue. Try using a saucepan to boil water and if the taste is no longer present, this is most likely the cause. This will be more noticeable with new kettles and should go away with time, but try boiling fresh water each time to reduce the issue. Rinse new kettles well before using them.
  
  
• Ensure that filling loops on central heating boiler are removed when not in use, as there is a possibility of water from the boiler reaching drinking water taps.