Public Water Supply Information 96% of all Public Water Supplies utilize ground water as their source 96% of all Public Water Supplies utilize ground water as their source Approximately 52% of the population served by public water systems is served by systems utilizing ground water Approximately 52% of the population served by public water systems is served by systems utilizing ground water The remaining population is served by systems using surface water - mostly very large systems The remaining population is served by systems using surface water - mostly very large systems