With warmer weather on the way, we're reminding visitors to stay safe when enjoying our reservoirs.
Our reservoirs are wonderful places to walk, enjoy nature and take in the scenery, but they are working water sources and swimming is not permitted at any of our sites.
Recent reports have highlighted the dangers of open water swimming, with at least 15 people losing their lives after getting into difficulty in open water during the recent heatwave. National Water Safety Forum figures also show that 202 people died from accidental drowning incidents across the UK in 2025.
Why are reservoirs dangerous?
While reservoirs may look calm and inviting, they can contain hidden dangers that are not always visible from the shore.
These include:
- Very cold water temperatures, even on hot days, which can lead to cold water shock
- Sudden changes in depth
- Deep silt that can trap feet
- Submerged machinery and pipework
- Hidden branches, plants and underwater obstacles
- Blue-green algae, which can be harmful to people and animals
- Remote locations that can make it harder for emergency services to reach someone in difficulty
A message from our Head of Health and Safety
Mike Pickard, Head of Health and Safety at South East Water, said:
"We're privileged to have such wonderful open spaces for the public to enjoy during periods of hot weather, but we must prioritise every visitor's safety.
"Reservoirs may seem like a good place to swim or cool down, but they can contain hidden dangers which are not always obvious from the bankside.
"Our advice is never to swim at any reservoir unless it is part of an organised event where the risks are suitably managed and first aid support is available."
Planning a visit?
South East Water has two reservoirs that are open to visitors all year round:
- Ardingly Reservoir, West Sussex: A popular destination for walking, wildlife spotting and enjoying the outdoors.
- Arlington Reservoir, East Sussex: A peaceful location offering scenic walks and opportunities to observe local wildlife.
If you're planning a visit this summer, please enjoy the views, stick to designated paths and stay out of the water.
Find out more about our reservoirs here.(opens in a new tab)
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