4 causes of bad tap water

Drinking water in England and Wales is of a very high quality and is usually safe to drink.

However, if you notice a change in the taste, colour or smell of the water from your tap, you should seek professional advice from your water company or a plumber immediately.

What causes bad tap water?

1. Chlorine as a disinfectantThe water industry uses chlorine to maintain hygienic conditions within the public water supply network of pipes.

   A guideline of 5mg/l for chlorine as a residual disinfectant in drinking water has been set by the World Health Organisation, and most water companies in England and Wales keep their levels below 1mg/l, meaning that risk of harm is unlikely. Your water supplier will provide you with a free water quality report upon request and you can check the Chief Inspector’s Annual Report on each water company here.

   If you are particularly sensitive to the taste of chlorine in your local tap water, a water filter can be used to dilute the flavour.

2. Seasonal water quality effectsAbout half of our drinking water comes from rivers and reservoirs. In summer, these waters occasionally develop a musty, earthy smell or taste due to natural environmental changes such as the growth of algae.

   By law, water companies are required to treat their supply, but you may still notice a hint of savoury change, particularly in extremely hot conditions.

   Again, contact your water company if you are concerned – you will find their contact details on the back of a recent water bill.

3. A change in water supply or moving homeThe natural properties of water vary from area to area because it picks up minerals from rocks as it flows across and through the ground. This means that hard water in a particularly chalky area will taste different to soft water from a reservoir in the hills.

   Most people prefer the composition of water similar to that they drank as a child but all water is extensively tested throughout England and Wales. With this is mind, there is little need for concern if your palate detects a change in taste when you move homes or if your water supplier switches source or instils a new process of water treatment.

4. Plumbing troublesWater may pick up traces of substances from your plumbing and water fittings or appliances.

   Under such circumstances, you may notice:

   • metallic or bitter tastes from copper, iron or galvanised pipes
   • plastic tastes from plastic pipes, kettles, tap inserts etc.
   • rubbery tastes from tap washers
   • TCP type taste from the reaction of chlorine with chemicals in rubber hoses, kettles, tap washers etc.
   • musty tastes from stagnant or warm water in seldom used sections of plumbing
   • salty or chemical tastes due to faulty or incorrectly fitted treatment devices

   If you suspect there is a problem with your plumbing, call a professional plumber to inspect your water supply and resolve the issue as quickly as possible.

Please remember; only drink water from the cold tap in the kitchen. This is because water from the hot taps and both taps in the bathroom may come from a water tank rather than a treated public water flow, and you may be putting your health at risk if you drink water that has not passed industry health standards.