Surface water resources are important components of savanna landscapes, supplying large populations of wildlife with drinking water critical for thermoregulation and digestion. However, little is known about the behavioural or physiological influence of water quality on wildlife health. East African savannas are well known for their migrating populations of ungulates coinciding with seasonal and spatial patterns of forage. In the Serengeti ecosystem, seasonal rainfall, high wildlife abundance and spatially variable soil composition result in temporal and spatial differences in surface water quality. Furthermore, nutrient enrichment from dissolved minerals and animal waste transported in runoff drive bacterial and algal blooms. Previous studies have suggested that water quality may be a factor in the migratory behaviour of wildebeest as poor quality water can have significant health consequences for ungulates, including depressed milk production and reduced food conversion. This paper examines the hypothesis that water quality in the southern Serengeti plains exceeds expected maximum tolerance limits at the end of the wet season – when migratory wildlife move northward, away from this region. Data collected during the migration's movement over 3 years are examined to determine if regional differences in water quality are physiologically meaningful and how the consumption of poor quality water may influence wildebeest nutrient intake. With increased demand for surface water resources from human populations, growing climatic uncertainty and significant changes in land cover outside of protected areas, the influence of water quality on animal behaviour needs to be considered for future management strategies. Copyright © 2012 John Wiley & Sons, Ltd.