WATER PURIFICATION – a process which removes specified contaminants from a water source.

WATER DISINFECTION – a purification process which kills or removes biological contaminants such as cysts, bacteria, viruses, protozoa, etc. from a water source.

Water that has been disinfected may still be polluted with contaminants that are not affected by the disinfection treatment. In some cases, additional contaminants may actually be added to the water during the disinfection process. For instance, the process of chlorination nearly always adds some disinfection by products. Boiling water will actually concentrate inorganic contaminants.