Chemical Tastes and Smells

The chemical taste of your drinking water is likely caused by the rubber and plastic materials used in household appliances and fittings. These plastic fittings include coffee maker gaskets/seals, tap washers, and hoses fitted to the inlet of washing machines and dishwashers.

These tastes do not come from the water pipes but are formed within the materials that make up certain materials. These plastic and rubber materials contain ‘phenols’ and related substances which can cause unpleasant tastes or odors. Also, low levels of chlorine may react with these chemicals to produce other taste-causing substances.

Although these substances can cause unpleasant tastes in hot drinks at very low levels (parts per trillion in some cases), they aren't harmful to health at the levels normally detected.

Chemical taste issues can come and go due to one or a combination of the following factors:

  • Changes in pressure - the pressure of your water supply is slightly higher at night and when fewer people are using water. This increased pressure can cause a slight expansion in the rubber hoses (like a long thin balloon) attached to washing machines and dishwashers. When a tap on your property is used, the pressure reduces and the expanded rubber pipe collapses and squirts water back into the incoming supply.

  • Standing water - water left in your pipes overnight or when your property is empty is far more likely to pick up any taste-causing substances from unapproved materials. Running your tap for a few minutes prior to use will solve this.

  • Washer deterioration - certain types of washers degrade with time. Because the ‘break-up’ of these washers isn’t a continuous process, the taste may come and go.​

Fixing the Problem?
  • Coffee makers - If you only notice the taste in hot drinks, try boiling water in a clean saucepan. If the taste is no longer present, it’s likely due to the gasket that seals the components inside of the coffee maker. This is often most noticeable with new coffee makers.

    The problem may go away with time if the coffee maker is new. Boiling fresh water each time may also help to keep the taste to a minimum. If the problem persists, you may like to contact the manufacturer for their advice.

  • ​Washing machines and dishwashers - Chemical tastes can sometimes relate to the hose which transfers water from your supply pipe to dishwashers and washing machines. Increases in water pressure can result in the flexi-hose expanding like a balloon – when the pressure is released, the hose collapses and can squirt water back into your supply pipe.

    This water can then mix with your incoming water. To stop this, try shutting off the flexi-hose by turning off the valve that supplies your cold water to the appliance when it’s not in use. This advice is also given by many manufacturers.

    If the location of the valve makes it difficult to access or operate easily, you could consider asking a plumber to do one or more of the following:

    ■  ​​Move the valve to a more accessible place so it’s easier to use.

    ■  Move the valve to a position after the draw-off point of the kitchen tap.

    ■​  Fit a non-return valve (also known as a check-valve) at the start of the hose.

    The check-valve prevents any water that’s been in contact with the flexible hose from coming back into your water supply. In our experience check-valves resolve many of these types of taste complaints.
  • Tap washers - Sometimes, the washer inside kitchen taps may be the cause of an unusual taste in your drinking water.

    If there is a second main fed tap in the house, try using water from this. If no taste is noticeable then the cause is probably the tap washer in the original tap. If no other suitable tap is available, run the tap for a short time before tasting the water.

  • ​Other hoses and fittings - Many modern kitchen tap fittings use flexible or braided hoses and other rubber-like materials. Some of these fittings can create taste problems. The best way to eliminate these is to ensure that all your drinking water fittings are approved.

    Though it is never recommended to install an unapproved product to your drinking water pipe, it is not illegal to sell them and many unapproved plumbing products are available. All approved products should be clearly marked and labeled.

Bedford Regional Water Authority
1723 Falling Creek Road • Bedford • VA 24523

Chemical Tastes and Smells