<p>In this work, a novel and highly sensitive plasmonic sensor depending on attenuated total reflection (ATR) using Kretschmann configuration is developed for drinking water quality detection through the fluoride contamination monitoring in the range of 0–20 ppm (part per million). The suggested sensor consists of CaF₂ prism with thin films of P3HT:PC₆₁BM organic compound mixture followed by a silver layer deposited on its surface (CaF₂/ P3HT:PC₆₁BM/Ag/water sample). The drinking water sample is positioned on the surface of a silver layer. The index of refraction of drinking water changes as the contamination of fluoride varies. The acquired resonance angles depend on the refractive index of the drinking water samples that dropped over the sensor surface. Consequently, the suggested sensor can be used to identify the contamination of fluoride ions in water samples. An accurate numerical finite difference time domain (FDTD) method has been applied to study and evaluate the suggested sensor through the angular interrogation method of optical reflectance. The materials and the geometrical parameters have been tailored to improve sensor performance. The optimized sensor has a sensitivity of 315 deg/RIU, quality factor (<i>Q</i>) of 73.63, figure of merit (FOM) of 297.23 RIU⁻¹, detection accuracy (DA) of 0.94 deg⁻¹, and minimum reflectance (<i>R</i>_min) of 0.047. As a result, we think that the suggested sensors may lead the way for cost-effective and accurate detection of different pollutants of drinking water which is vital in water quality detection, help in satisfying the third and sixth goals of sustainable development goals (SDGs), and help in healthcare by early detection of water quality of wells and other sources. In addition, the suggested sensor can be fabricated with cutting-edge technologies.</p>