What is Legionella?

Legionella is a hazardous bacteria found in water. The risk is higher in water stored at temperatures between 20 and 45 degrees and water tanks that contain stagnant or recirculated water.
If ingested, Legionella can cause Legionnaire's disease. It makes you seriously ill, causing high fevers, headaches, coughing and nausea, but can be treated easily with antibiotics.