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Abstract Productivity in estuaries is dependent upon nutrient influx and cycling. However, increasing urbanization and socioeconomic activities continue to influence nutrient dynamics and thus estuarine organisms. The western Gulf of Mexico coast lies in a climatic gradient that drives differences in hydrology among Texas estuaries providing a natural experiment to determine how hydrology affects nutrient biogeochemical budgets. One modeling approach is the land-ocean interaction in the coastal zone (LOICZ) guideline. The LOICZ budgets were calculated for all major estuaries in Texas to compare long-term water, salt, and nutrient budgets. The budgets were calculated based on daily averages using various datasets from multiple Texas agencies. Separate nutrient and water budgets were calculated for the Lower Laguna Madre Estuary and the Upper Laguna Madre Estuary. The climatic gradient along the coasts drives the water budgets because precipitation difference is the main factor influencing inflow balance. Inflow balance is the main factor influencing differences in salinity and nutrient concentrations among the estuaries. However, elevated nutrient levels in two estuaries are caused by urbanization, return flows, and agricultural runoff. Draining the adjacent large city of Houston, Texas, USA, the Trinity-San Jacinto Estuary had higher daily average dissolved inorganic phosphorus (DIP) and total phosphorus (TP) levels compared to the other estuaries. These high levels are likely caused by high use of detergents and wastewater return flows that include fecal and urine waste. At the opposite end of the coast, the Upper Laguna Madre Estuary has higher total Kjeldahl nitrogen (TKN) compared to the other estuaries due to its unique features including hypersalinity and low inflow dominated by sewage and agricultural runoff. The Texas budgets are comparable to budgets in estuaries in Asia, South America, and Africa with similar hydrology. This study demonstrates that hydrology controls nutrient transport and altered hydrology can alter the nutrient dynamics. Altered nutrient dynamics can affect biological productivity and water quality in estuaries.