Millions of households across the UK have been thrust into a public health emergency as a major water company issues an urgent boil water notice following the discovery of a dangerous parasite.
The shock warning, affecting large swathes of London and the Home Counties, was announced after cryptosporidium was detected in the water supply. This microscopic parasite can cause severe gastrointestinal illness, with symptoms including profuse diarrhoea, vomiting, and stomach cramps.
What Areas Are Affected?
The alert primarily impacts customers of Thames Water in the following postcode areas:
- SW13, SW14, SW15, SW16, SW17, SW18, SW19, SW20
- KT1, KT2, KT3, KT4, KT5, KT6, KT9
- TW1, TW2, TW3, TW4, TW7, TW8, TW9, TW10, TW11, TW12, TW13, TW14, TW15, TW16, TW17, TW18, TW19, TW20
- SM1, SM2, SM3, SM4, SM5, SM6
- CR4, CR5, CR6, CR7, CR8, CR9, CR44, CR90
- WD3, WD4, WD5, WD6, WD7, WD18, WD19, WD23, WD24, WD25
- HA5, HA6, HA7
- UB1, UB2, UB3, UB4, UB5, UB6, UB7, UB8, UB9, UB10, UB11
What You Must Do Now
Residents in the affected zones are being instructed to take immediate action:
- Boil all tap water intended for drinking, cooking, or brushing teeth. Bring it to a rolling boil and let it cool.
- Do not use water from kitchen taps or bathroom taps for consumption without boiling it first.
- Use boiled or bottled water for preparing food, making ice, and for pets.
It is safe to use unboiled water for washing, bathing, and flushing toilets.
Understanding the Health Risks
Cryptosporidium is a waterborne parasite that causes an illness called cryptosporidiosis. The UK Health Security Agency (UKHSA) warns that symptoms typically appear 2-10 days after infection and can last for several weeks. Those with weakened immune systems, the elderly, and young children are particularly at risk of severe dehydration and more serious complications.
Thames Water has stated it is "urgently investigating" the cause of the contamination and is working to resolve the issue. In the meantime, they are advising all customers to follow the boil water notice until further updates are provided.
