One in three people globally are challenged to live on hazardous, unsanitary water, and this relates to higher risks of death and development of diseases. According to scientific research, activated charcoal can be used to clean water contaminants to help make water safer.•Carbonization: this study demonstrates an inexpensive method of producing activated charcoal that can be performed in any setting using locally available biomass materials.•Activation: thermal air oxidation between moderate temperatures of 450–550 °C.Our data indicate that this technique produces charcoal with an adsorptive capacity near to that of commercial-grade charcoal as demonstrated by spectrophotometric analysis. This simple approach to charcoal activation may benefit rural communities where sources of sanitary water are low or nonexistent.