New Year-Round Blue-Green Algae Warning Signs Installed Across Cumbria
New permanent warning signs are being installed around Windermere and other parts of Cumbria to help people recognise the dangers of blue-green algae.
Around 40 signs will be placed at locations around Windermere, with a further 40 introduced across the wider county. The project is being delivered by the Love Windermere Partnership and funded by the Environment Agency.
Unlike temporary warnings used when a bloom is confirmed, the new signs will remain in place throughout the year. They explain how to recognise possible algae, the risks it can pose and how suspected blooms can be reported.
The signs do not necessarily mean blue-green algae is currently present at that exact location. Instead, they provide lasting safety advice because blooms can appear quickly and move as weather conditions change.
What Is Blue-Green Algae?
Blue-green algae, also known as cyanobacteria, occurs naturally in lakes, reservoirs and slow-moving rivers. It is more likely to form visible blooms during periods of warm, calm weather.
A bloom can make the water appear green, blue-green or brown. It may also look like green flakes, small clumps, paint or scum floating on the surface. Some blooms can produce an earthy or musty smell.
Not every bloom is toxic. However, it is impossible to tell whether it is dangerous simply by looking at it. People are therefore advised to avoid suspicious water and treat any possible bloom with caution.
What Are the Risks?
Contact with affected water can cause skin rashes and eye irritation. Swallowing water containing harmful algae may also lead to vomiting, diarrhoea, fever or pain in the muscles and joints.
The risk can be especially serious for dogs and other animals. Dogs may swallow affected water while swimming or lick algae from their fur afterwards. In severe cases, exposure can be fatal.
Anyone who sees water that may contain blue-green algae should:
- Avoid entering or swimming in the water
- Keep children away from the affected area
- Keep dogs on a lead and out of the water
- Avoid drinking or swallowing untreated lake water
- Report the suspected bloom
The new signs will direct visitors to the UK Centre for Ecology and Hydrology’s Bloomin’ Algae app. The app allows people to report suspected blooms and view sightings submitted by other users.
Reports can also be made through the Environment Agency’s 24-hour incident hotline on 0800 80 70 60.
Blooms Reported Across the Lake District
Blue-green algae has been reported at several Cumbrian locations during 2026. Confirmed or plausible reports have included areas around Windermere, Coniston Water, Derwentwater, Ullswater, Thirlmere, Grasmere, Killington Lake and Talkin Tarn.
However, algae can disappear, break apart or move to another part of a lake. A location that was affected several days earlier may later appear clear, while a new bloom may form elsewhere.
Visitors should therefore check the water themselves, read any local notices and review the latest Environment Agency information about reported blooms before swimming or allowing pets into the water.
Helping Visitors Make Safer Decisions
Liz Cheslett-Davey, catchment co-ordinator at the Environment Agency, said the signs formed part of a wider effort to improve access to water safety information.
She explained that blue-green algae can appear quickly and that the conditions behind blooms are not always easy to predict. Clear signs, online information and reports made through the app should help people make informed choices before entering the water.
A series of short educational films has also been created to help residents and visitors learn more about algae.
The permanent signs should make warnings easier to find, particularly for people who may not check official reports before visiting a lake. They will also serve as a reminder that blue-green algae is not only a summer concern and that conditions should always be checked before people or pets enter the water.
