Several surveys have been conducted in Nicaragua between 1996 and 2015 confirming the presence of high levels of arsenic (>10 μg/L). In this paper, these peer-reviewed (n = 2) and non-peer reviewed sources (n = 14) have been combined to provide an extensive overview of the arsenic contamination of drinking water sources in Nicaragua. So far, arsenic contamination has been detected in over 80 rural communities located in 34 municipalities of the country and arsenic poisoning has been identified in at least six of those communities. The source of arsenic contamination in Nicaragua is probably volcanic in origin, both from volcanic rocks and geothermal fluids which are distributed across the country. Arsenic may have directly entered into the groundwater by geothermally-influenced water bodies, or indirectly by reductive dissolution or alkali desorption, depending on the local geochemical conditions.