Abstract: This research focuses on an anomaly observed by the radon-thorium analyzer in Wen’an well. It exhaustively records the workflow of grassroots water stations to verify fluid anomalies, including basic data collection, instrument condition inspection, and investigation of the surrounding environment. Through on-site sampling, the hydrochemical data of Wen’an well are obtained for the first time, determining it to be HCO₃—Na⁺ type water. The analysis shows that the recharge sources include mixed shallow-surface substances and deep-groundwater recharge, with active water-rock interactions occurring, and no ionic equilibrium being reached. The study comparatively analyzes the underground fluid data, seismic activity, hydrochemical data, parallel observation data, and morning-afternoon comparative observation data of Wen’an well, ruling out influences such as instrument malfunctions, environmental interference, and meteorological factors. It is comprehensively determined that the high-value radon anomaly in Wen’an well present since May 17, 2024 may be related to the enhanced regional stress state. This research provides technical support and analytical ideas for the verification of earthquake precursor anomalies, and has important reference value for research in underground fluid disciplines, earthquake monitoring, and early warning systems.