<p>Electrochemical detection of toxic heavy metal ions is of great significance due to metals harmful impact on the environment. In this work, a reduced graphene oxide (RGO)-supported Ag/PANI nanocomposite electrochemical sensor was synthesized via oxidative polymerization for the detection of lead (Pb²⁺) and cadmium (Cd²⁺) ions in ground and surface water. The synthesized nanomaterials were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–Vis spectroscopy, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The Ag/PANI/RGO-modified glassy carbon electrode (GCE) exhibited higher reversibility compared to other modified electrodes (PANI/GCE and PANI/RGO/GCE) at a scan rate of 50 mV/s, which is attributed to the synergistic interaction among PANI, RGO, and Ag nanoparticles on the electrode surface. Furthermore, the Ag/PANI/RGO nanocomposite sensor was evaluated using the anodic stripping voltammetry technique, yielding excellent linear regression coefficients (R² = 0.9990 for Pb²⁺ and R² = 0.9977 for Cd²⁺). Under optimized conditions, the Ag/PANI/RGO/GCE sensor demonstrated a wide dynamic linear range (10–100&#xa0;µg/L), low detection limits (0.57&#xa0;µg/L for Pb²⁺ and 0.78&#xa0;µg/L for Cd²⁺), high sensitivity, and good recovery rates for the detection of heavy metals in water samples. Overall, the Ag/PANI/RGO/GCE-modified electrode shows strong potential as a reliable sensor for monitoring Pb²⁺ and Cd²⁺ contamination in ground and surface water.</p> Graphical abstract <p></p>