HP — Hemel Hempstead
Who supplies water in the HP postcode area?
Thames Water and Affinity Water supply addresses in HP, which covers Hemel Hempstead, High Wycombe, Aylesbury, Amersham and Berkhamsted. Water is not a market you can shop in — the supplier comes with the address.
Thames Water
Water and sewerageSupplies water and takes waste water across London and the Thames Valley. It is the largest water company in the UK by number of customers. In outer London and the home counties the taps are often supplied by Affinity Water or SES Water while Thames Water still handles the sewerage.
Affinity Water
Water onlySupplies drinking water to parts of Hertfordshire, Bedfordshire, Buckinghamshire, Essex, Surrey and north-west London. It does not take waste water away, so a second company — usually Thames Water, Anglian Water or Southern Water — handles sewerage and often bills for both.
More than one company appears here either because HP straddles a boundary, or because one company supplies the drinking water while another takes the waste water away. Your bill will say which applies to your address.
Places in the HP postcode area
A sample, not the full list. HP is the postcode area — the letters before the first digit — so it covers every HP outward code.
Check a different postcode
A few useful answers
Common questions
Who supplies water in the HP postcode area?
Thames Water and Affinity Water supply parts of the HP postcode area. The supplier is decided by where the property is, not by who lived there before you.
Can I switch water supplier in HP?
No. Household water supply is not a competitive market anywhere in the UK — there is one supplier for each address and no tariff to compare. What you can change is how you are charged, by asking for a meter.
Why does this page list more than one company for HP?
A postcode area can straddle a boundary, and in much of England the company that supplies the taps is not the one that takes the waste water away. Both appear here so you can check which applies to your address.
Do I need to open a water account when I move in?
Yes. Tell the supplier the day your tenancy starts and give an opening meter reading if the property has a meter, so you are not billed for what the last tenant used.
Where to confirm this
We hold the supplier at postcode-area level, which is coarse enough to be wrong at a boundary. These are the industry's own sources, and they settle it for a specific address.
- Water UK: find your supplier ↗
- the Consumer Council for Water: complaints and advice ↗
- Discover Water: bills by company ↗Sector average £639 a year for 2026–27.
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