Knowledge of the mean recharge elevation (MRE) of water resources is
important for informing conservation and protection practices where water security is threatened by population growth, urban expansion, and land and climate changes. In this study a Bayesian approach was developed and applied to determine the MRE of 682 surface water samples collected from the Central America region, where Pacific and Caribbean draining basins are characterized by distinct precipitation regimes, based on stable isotope comparisons between surface water samples and interpolated catchment precipitation. Different patterns in MRE were identified for Pacific and Caribbean samples: those collected from the Pacific slope are generally recharged at higher elevations relative to the sample mean catchment elevation (MCE), while those on the Caribbean slope are largely recharged at elevations lower than the sample MCE. The relationships between MRE and MCE for each slope were quantified as: MREP = 1.072 (MCE) + 45.65 and MREC = 0.9493 (MCE) – 28.24 (r2 = 0.93, MAE = 150 m (Pacific) and r2 = 0.76, MAE = 216 m (Caribbean)), and can be used to estimate the MRE of other regional water sources. Including catchment size and surface water site elevation (SWSE) as predictor variables improves MRE estimations because these variables influence the MRE:MCE relationships, especially on the Pacific slope (p <0.001 (Pacific) and < 0.05 (Caribbean) for both catchment size and SWSE). MRE, SWSE, and MRE-SWSE differences are generally greater on the Pacific slope, which hosts the majority of the region’s population and urban centers, corroborating the need to establish protections for the mountainous areas.