BACKGROUND: A simple point-of-use solar disinfection (SODIS) reactor was designed to treat 25 L of water and was constructed from a methacrylate tube placed along the linear focus of a compound parabolic concentrator (CPC) and mounted at 37 degrees inclination. Experiments were carried out over a 7 month period by seeding a 10(6) CFU mL(-1) concentration of Escherichia coli K-12 in 251 of well water or turbid water to mimic field conditions and determine the microbial effectiveness of the reactor. RESULTS: During periods of strong sunlight, complete inactivation of bacteria occurred in under 6 h, even with water temperatures <40 degrees C. Under cloudy and low solar intensity conditions, prolonged exposure was needed. Turbid water (100 NTU) was disinfected in 7 h with water temperatures > 50 degrees C. No regrowth of bacteria occurred within 24 h and 48 h following solar disinfection. The construction cost of this prototype reactor was approximately US$200 but with an expected lifetime of 10 years, the running cost of the reactor is expected to be US$0.002 L-1. CONCLUSION: This study confirms that significant water disinfection can be achieved using a low cost CPC-enhanced 25 L batch SODIS reactor. (C) 2010 Society of Chemical Industry