Abstract
We describe an outbreak of Legionnaires' disease linked to an exclusive cold-water source in a private residential setting in Yorkshire. The cold-water source was identified following microbiological testing of clinical and environmental samples. Legionella pneumophila was only detected in the cold-water system. Three cases were identified over the course of the outbreak: two confirmed and one probable. Conditions favourable to bacterial growth included system 'dead legs' and significant heat transfer to the cold-water system. We describe challenges in implementing control measures at the venue and highlight the importance of using enforcement powers, where necessary, to reduce risk.