Customers occasionally contact Anglian Water to report that their tap water has an unpleasant taste, often described as TCP, metallic, chemical, medicinal, or bitter. Sometimes this taste occurs only in boiled drinks, or when a glass of water has stood for a period of time.
Anglian Water, like all other UK water companies is required by law to disinfect the water supply, and for this purpose chlorine is added during the water treatment process. These tastes and odours can be caused by the reaction between chlorine present in tap water and plastic or rubber components found in common household appliances, such as kettles, tap washers, and the hoses connecting dishwashers and washing machines to the mains supply.
Why is chlorine used?
Water companies have a legal requirement to disinfect all public water supplies. It is essential that drinking water is always safe to drink and contains no organisms that can cause illness. Adding chlorine is one of the most effective methods of disinfecting water supplies.
What can I do to find the cause?
When the taste is noticeable, the following suggestions may help to find the origin of the problem.
Rule out your kettle as the source of the problem
If you only notice the taste in hot drinks, try boiling water in a saucepan. If the taste is no longer present then the likely cause is the kettle gasket that seals the elements to the side of the kettle. This is often most noticeable with new kettles.
What’s the solution?
The problem may well go away with time if the kettle is new. Boiling fresh water each time may also help to keep the taste to a minimum. If prior to boiling your water, you fill a container with tap water, cover it, and leave it in the fridge for an hour or so, this will help to reduce the likelihood that any reaction will take place. If the problem persists, you might like to contact the manufacturer for further advice.
Rule out the washing machine as the source of the problem
To confirm whether the dishwasher or washing machine hose is the cause, isolate the hose and taste the water.
What’s the solution?
If this solves the problem, you could fit a non-return valve on the end of the hose where it connects to the pipework. If the location of the valve makes it difficult to access or operate easily, you might like to consider asking a plumber to do one or more of the following:
1. Relocate the valve to a more accessible location so that operation is easier.
2. Relocate the valve to a position after the draw-off point of the kitchen tap.
3. Install a non-return valve at the start of the hose.
4. If a non-return valve is already installed, then this may be faulty and so should be replaced.
Rule out the tap washer as the source of the problem
The likelihood of an unpleasant taste being imparted to tap water is increased if the washers used do not conform with British or equivalent European standards or a specification approved by the regulator. The Water Regulations Advisory Scheme (WRAS) can provide advice on appropriate tap fittings. Call 01495 248 454 for advice. If there is a second mains fed tap in the house then you might like to 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 then run the tap for a short time before tasting the water. It is worth noting that internal stop taps are also fitted with washers.
What’s the solution?
Replace the washer with an approved (non-phenolic or synthetic) washer. In most cases, these suggestions will help you find the problem and will provide a simple solution. However, if you try them and are still unable to find the cause of the problem and require further assistance, please call the Anglian Water helpline on 08457 145 145.