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Regional water quality guide

Tap Water in South East EnglandPFAS notice

South East England water is hard to very hard (180–310 mg/L CaCO₃). Supplied by Southern Water, South East Waterand others. Enter your postcode for your exact zone report.

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Water hardness
Hard To Very Hard
PFAS notice active
Water companies
Southern Water, South East Water, Affinity Water, Portsmouth Water
Enter postcode to confirm yours
Main water sources
chalk and greensand aquifers of the North and South Downs, p…
Surface & groundwater

The South East of England is served by four main water companies: Southern Water (covering Kent, East Sussex, Hampshire, and the Isle of Wight), South East Water (covering parts of Kent, East Sussex, Surrey, Sussex, and Hampshire), Affinity Water (covering parts of Hertfordshire, Essex, and Bedfordshire, as well as parts of Surrey), and Portsmouth Water (covering Portsmouth, Havant, and surrounding areas). This is one of the most water-stressed regions of England, with high demand and limited natural resources compared to wetter parts of the UK.

Water hardness across the South East varies by locality and source, but most of the region has hard to very hard water. The chalk North and South Downs dominate the geology of Kent, East Sussex, and Hampshire — water filtering through chalk picks up substantial calcium and becomes hard. Brighton, Hove, and most of Kent have very hard water exceeding 250 mg/L CaCO₃. Southampton and Portsmouth areas tend to have hard water in the 200–260 mg/L range. Oxford and the Thames Valley are hard to very hard (250–280 mg/L) due to chalk aquifer sources.

Southern Water and water quality concerns

Southern Water has faced serious regulatory and legal challenges in recent years. In 2021, the company was fined £90 million for illegal sewage dumping — the largest penalty in Ofwat's history at the time. Multiple PFAS improvement notices are active. Southern Water has invested substantially in infrastructure improvements under regulatory direction. Water quality testing compliance remains high despite these operational and regulatory challenges.

PFAS in the South East

Multiple water companies in the South East hold active DWI PFAS improvement notices: Southern Water, South East Water, and Affinity Water are all affected. The South East's chalk aquifer sources concentrate PFAS that have entered groundwater from industrial, military, and agricultural sources over decades. PFAS are difficult and expensive to remove from groundwater — the improvement programmes reflect long-term investment commitments rather than emergency responses.

Water companies in South East England
Major cities in South East England
Frequently asked questions
Is South East England tap water safe to drink?

Yes. Tap water in South East England is safe to drink. UK tap water is subject to rigorous regulation and testing. Over 99.9% of samples pass legal standards each year. Enter your postcode above for your specific zone's data.

Is South East England water hard or soft?

South East England has hard to very hard (180–310 mg/L CaCO₃) water. Heavy limescale on appliances is expected. A water softener or RO filter is strongly recommended.

Which water companies serve South East England?

South East England is served by: Southern Water, South East Water, Affinity Water, Portsmouth Water. Enter your postcode to identify your exact water company.

Does South East England tap water have PFAS?

South East England has water companies with active DWI PFAS improvement notices. Enter your postcode to check your zone.

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