Algae bloom at Testwood Lakes

Testwood Lakes nature reserve © Southern Water 

An algae bloom at Testwood Lakes has resulted in some temporary restrictions at the nature reserve

In response to the development of blue-green algae at Testwood Lake in Totton, a Hampshire & Isle of Wight Wildlife Trust spokesperson said: “During warm dry weather such as that we’ve been having over the past few months can lead to a bloom in Blue Green Algae (BGA). Unfortunately this algae produces powerful toxins, which if ingested can cause serious short term and long term health problems for both humans and dogs.

“We are therefore asking visitors to keep their dogs out of the water at Testwood Lakes nature reserve until further notice. People are prohibited from swimming at Testwood Lakes year round, but it is particularly important that everyone avoids the water at the moment.”


More information


  • Blue Green Algae (BGA) is naturally occurring bacteria that occurs in freshwater bodies. They only pose a health risk if they reach certain levels.
  • Ingestion of BGA can cause diarrhoea, vomiting, dizziness and breathing difficulties and in extreme cases long term kidney and liver problems. The impact on dogs can be even more severe.
  • Southern Water (the Wildlife Trust’s landlord at Testwood) carries out regular monitoring of the lakes to identify whether a bloom is occurring.
  • We were recently informed that counts in Testwood Lakes had increased dramatically and stood at a level that could pose a long term threat to human health if ingested. We immediately erected warning signs and increased patrols to discourage people from swimming and from allowing dogs into the lakes.
  • We will remove warning signs on site and update our website when we are confident that the water is safe again.