The ESG “Protex” is an electro-chemical device being developed to provide continuous disinfection of recirculating water systems providing protection against Legionella and other pathogenic bacteria. The unit could allow such systems to be operated safely at lower temperatures, thereby reducing energy consumption, and improving safety whilst reducing the need for chemical biocides. This project will optimise the design, improve the durability, reduce the manufacturing costs and assess the performance of the prototype. Real case data will be produced on the efficacy of the device to exterminate pathogenic bacteria in buildings of different size and type. Recommendations on optimised design and reduced manufacturing costs as well as validated evidence on the efficacy of the device in both laboratory and field will be disseminated to relevant industries and users and help bring the technology to market.