Groundwater to Surface Water Conversion in the Houston-Galveston Region: Impact of Mandates on Water Quality, Subsidence, and Water Rates

Legislative mandates have resulted in large-scale conversion from groundwater to surface water sources of supply for Public Water Supply Systems in Harris and Galveston Counties, Texas. Geographically-defined Regulatory Areas in the region are governed by the Harris Galveston Coastal Subsidence District. The district's mission, to end subsidence or loss of land elevation by allocating water usage by Area, has focused attention on potential health hazards and monetary issues related to substandard water quality and increased consumer utility rates. Study variables of: (1) Total Hardness (TH); (2) Total Trihalomethanes (TTHMs) concentrations; and (3) Water Utility Rates ($), were compared for each water source because of their suggested impacts on human health (TH:CVD; TTHMs:Cancer) and relative economic welfare (Utility Rates: $) as byproducts of current mandate requirements. Strong evidence of statistically significant differences in water quality parameters, and utility rates of groundwater and surface water source data, suggest that regulations dictating conversion need review and possible amending. This presentation describes the results of a 2-year study of the issues regarding conversion of Public Water supplies from groundwater to surface water.