Photocatalytic disinfection of water was evaluated in a 100 m long reactor using titanium dioxide (TiO2) as photocatalyst immobilized in mortar and solar radiation as the main driving force. The aim of the experimental assessments was reduce the bacterial concentration level in water as function of the solar radiation available on every experiment. In order to achieve this objective, Escherichia coli (ATCC 25922) was used as model microorganisms at bacterial counts in water as high as 103 and 104 UFC/100mL. Under the experimental conditions tested, the reactor tested reached from 80-90% bacterial abatement working at 1L/s of flow rate. Tests carried out to determine the effect of solar disinfection (SODIS) on the system demonstrated that bacterial abatement up to 40% was reached by using solar radiation alone without adding any photocatalyst and suggested a strong synergistic effect for the damages produced by the radiation in the bacteria and the photocatalytic process.