Recently Legionella pneumophila is the main causative waterborne organism of severe respiratory infections. Additionally, other Legionella species are documented as human pathogens. In our work we describe a rapid detection method which combines two advantages for sensitive and specific detection of the genus Legionella: the fast isothermal amplification method “Loop-mediated isothermal AMPlification” (LAMP), and a colorimetric detection method using the metal indicator hydroxynaphtol blue (HBN) which allows to determine an optical signal with a simple read out (with the naked eye). Moreover, we present two approaches for minimizing the assay volume using a stationary microchip LAMP and droplet digital based LAMP (ddLAMP) as promising high sensitive setups.