Effluent is initially treated in waste disposal lagoons near ridge of Gambier Limestone which is a widespread and important water table aquifer. Consequently the risk of groundwater pollution is high. There is also risk of collapse of the floor of the anaerobic lagoons by piping effects. The pollution potential of the aerobic lagoons is small as it is underlain by over 10 metres of impermeable sandy clay. Measurements should be made of the inflow and outflow for the anaerobic lagoons to determine their leakage and this with the water quality monitoring programme will determine if further investigations are necessary.