Water butts and Legionnaires Disease

From the Sunday Times, 15 July 2018. Warning from Public Health England Porton Down laboratories that 95% of water butts are contaminated with legionella bacteria.  Samples from 113 water butts showed that 107 were contaminated. Watering cans and low pressured sprays released few bacteria but if turned into a spray, the number of microbes floating in the air surged. The RHS has recommended that you use only clean water to spray or hose the garden.  Fountains, mist jets etc are banned from their garden shows for several years.