Accurate estimation of groundwater recharge is essential for sustainable aquifer management, especially in semi-arid regions with water scarcity. This study assesses four independent methods-Water Table Fluctuation (WTF), Water Balance Method (WBM), Chloride Mass Balance (CMB), and Stable Isotope (SIs) analysis-to quantify recharge and determine its sources in the Damghan aquifer, Iran. Recharge estimates range from 2.5 to 40.64 million cubic meters per year (MCM/year), depending on the conceptual framework and assumptions of each method. The WTF method gave the highest value because it records all causes of water-level rise, such as direct recharge, irrigation return flows, and lateral inflows, without separating them. Yet this approach remains sensitive to fluctuations unrelated to recharge; for example, seasonal shutdowns of pumping wells in winter lower abstraction and lead to temporary water-level rises that can be mistaken for recharge. The WBM produced a more moderate and hydrologically realistic estimate (similar to 25 MCM/year), as it accounts for both natural and human-related components. In comparison, the chemically based methods (CMB and SIs) yielded lower, conservative estimates (4.9 and 2.5 MCM/year, respectively). These methods focus on recharge from direct precipitation via vertical infiltration and exclude irrigation return flows and boundary inflows. These results show the need to consider methodological context when interpreting recharge figures. By combining physical, chemical, and isotopic techniques, the study demonstrates how the methods complement each other in separating contributions from precipitation, irrigation return flows, and lateral inflows. Among the approaches, WTF and WBM stand out as practical options for semi-arid aquifers where multiple recharge pathways occur together. This combined view improves the reliability of recharge assessments and offers practical support for sustainable groundwater management in water-scarce areas.