New spectrophotometric method for Bisphenol A determination has been developed according to the current study. A colored complex called Bisphenol A can be obtained through the combination of benzidine in an alkaline solution. The chemical reaction produces a dark yellow compound which shows absorbance at 452 nm. The analysis showed Beer's law compliance from 5–14 g/mL with R2 value at 0.999 and LOD at 0.3470 g/mL while LOQ at 0.1190 g/mL. This reaction solution demonstrated a molar absorptivity value of 2872.8 L·mol⁻¹·cm⁻¹ accompanied by a relative standard deviation of 0.00125%. The recovery value for this method reached 102.2311% and the Sandal sensitivity measurement produced a result of 0.07937 g/mL. Bisphenol A detection through this method succeeded in a series of wastewater samples which included measurements from Tap water along with Diyala, Khresan, and Mahroot Bridge. The technique exhibited a strong correlation and excellent conformity to Beer’s law while ensuring high precision, accurate detection, and low measurement limits. The ability to detect BPA at trace levels was achieved by optimizing reaction parameters and reagent dosages. This method proved to be a reliable tool for assessing BPA contamination in drinking water sources and industrial effluents, as demonstrated by its application to environmental samples from various sources. Its cost-effectiveness, ease of implementation, and high sensitivity make it an effective monitoring approach for environmental assessments.