Chlorine and disinfectant taste and smells

Is there a chlorine or chemical taste or smell to your water, have you noticed it in your tea or coffee or perhaps you’ve just moved to a new area and it’s stronger than you’re used to? Chlorine and a disinfectant type taste or smell are quite common in water, so here we explain why.

Chlorine taste - quick check list

My tap water:

• tastes like chlorine, bleach or water in a swimming pool
• tastes or smells of chlorine in cold drinks only
• tastes more noticeable first thing in the morning or early evening.

What causes it?

We add chlorine in very small amounts at our water treatment works, monitoring the levels 24 hours a day. It is a legal requirement to disinfect the water supply and make sure it’s safe to drink. 

Sometimes the chlorine is more noticeable, this is due to:

• your distance from the treatment works – the level of chlorine deteriorates over time, the closer you are the more noticeable it might be
• the water temperature – colder water holds chlorine for longer
• the time of day – first thing in the morning and early evening is peak time for water use, meaning the water has come more quickly from the water treatment works and may contain more chlorine 
• if there’s a burst main in your area or the emergency services have drawn water from our water mains, as above, the water may have come more quickly from the water treatment works.

Did you know?

The level of chlorine added at the water treatments works is usually up to 1 part per million (mg/l).Your local swimming pool is normally between 1.5 and 5 parts per million (mg/l).

What can I do?

• To remove chlorine, place a jug of water in the fridge for a few hours before drinking it
• Don’t keep it for over 24 hours - removing the chlorine means your water isn’t protected against bacterial growth
• If this doesn’t help or you also notice a taste or smell in hot drinks, it may be the chlorine’s reacting inside your plumbing. This is where water tastes metallic or like disinfectant. Sorting this is straightforward.

What causes it?

The chlorine we add to disinfect the water can react with some plastics and rubbers in your plumbing or kitchen appliances, giving it a bitter, metallic or disinfectant like taste. Even though this isn’t harmful, we agree it doesn’t taste very nice.

What can I do?

The problem can be solved quite easily, you just need to track down the source and follow our troubleshooting guide:

Is the taste only in hot drinks?

If it is, your kettle is probably the cause. Most kettles have plastic parts, even metal ones, which react with the chlorine. New kettles are particularly prone but they should quickly settle down. The plastic can also react as your kettle gets older, so if the taste persists you may want to replace it.

You can easily test this by boiling the water in a saucepan to see if the taste is still there. 

Could my washing machine, dishwasher or other appliance be the cause?

One of the hoses from a plumbed-in appliance could be the culprit. To check:

• isolate the supply to your appliance 
• detach the hose from the plumbing
• run the taps to flush through any water that’s been left standing in the hoses
• disconnect the hose for a few hours or overnight if possible 
• see if the taste has gone. If it has then your hose is the cause. To fix this, you’ll need a ‘check valve’ - a small valve you screw onto the top of the hose to prevent water flowing back into your pipework. You can buy it from most DIY stores or order free of charge here or contact us. 

How do I fit a check valve?

1. Switch off the cold water supply to the appliance. Look behind the appliance or where you think the flexible hose is connected to the plumbing. Turn off the isolation valve at the top of the hose. You may need to use a screwdriver to turn this
2. Unscrew the hose at the top, next to the valve you’ve just turned off and use a bowl to catch any water spillage
3. Check the round washer is present in the large end of the check valve and screw this onto the isolation valve (it will only fit the correct way round)
4. Check there’s a rubberwasher in the flexible hose and connect it to the check valve
5. Hand tighten check valve and flexible hose and then tighten with a wrench. Be careful not to over tighten and damage the plastic fitting
   Carefully open the isolation valve, checking for any leaks, and use the bowl to catch any drips
6. If there are any leaks, close the isolation valve and re-tighten the connections
   Slowly open the isolation valve again and monitor leaks for 15 minutes.

Could it be coming from my tap?

• If you don’t think it is a hose or the kettle causing the problem or if you have had new taps fitted recently, one of the tap washers may be causing the taste.
  New tap washers or old worn washers can react with chlorine in the water. 
• Try fitting a non-phenolic washer
  Choose an approved tap fitting. If the water tastes funny from all your mains fed taps, try changing the washer on your stop tap. Still stuck? Try our self diagnosis tool to help solve the problem.
  Still stuck? Try our self diagnosis tool to help solve the problem.
• If you’re a business customer, contact your provider for more information.