Over the last 3 years, during the routine quality monitoring of the shared and shortage water of the North Eastern Aquifer (NEA), 37 groundwater samples were collected from groundwater wells by the National Agricultural Research Center (NARC) and analyzed by NARC laboratories. Obtained results indicate that pH, sodium, magnesium, potassium, sulfate, and fluoride values are below the WHO guideline values. However, current results exceeded the WHO limit value regarding TDS, calcium, total hardness, chloride, and nitrate in 17, 3, 2, 1, and 7 samples, respectively. Fluoride contents were in the 0.18–0.55 mg l−1, below the WHO recommended value. However, fluoride exceeded the international standards in the groundwater of the Coastal Aquifer (in the Gaza Strip) mainly due to weak infrastructure, excessive pumping, and seawater intrusion into groundwater. Therefore, the development of new monitoring techniques is of high importance. In this study, the zirconium chrome azurol B 1:2 complex was prepared and applied as a fluoride reagent to evaluate fluoride in an actual groundwater sample collected from NEA. In the proposed method, fluoride reacts with zirconium complex where the color changes, which are proportional to fluoride concentration, are measured by spectrophotometer at the wavelength of maximum absorbance (539 nm). The method’s sensitivity is −0.107 μg ml−1. The detection limit and quantitation limit are 0.2 mg l−1 and 0.5 mg l−1, respectively. The correlation coefficient is 0.990, and the percentage recovery of 1.0 mg l−1 fluoride is 94.8. The percentage recovery was taken as the average of 10 replicates.