Exposure to fluoride (F-) in drinking water remains a global public health concern, particularly in arid regions with geogenic contamination. The study quantified non-carcinogenic hazard and disease burden associated with fluoride exposure in drinking water in Zarrin Dasht County, Iran, and evaluated differences between tap water and reverse osmosis (RO)-treated water. Sixty percent of tap water samples exceeded the World Health Organization (WHO)-recommended value (1.5 mg F- /L), with an average concentration of 1.78 mg F- /L, while all RO-treated samples were below 0.5 mg F-/L. Deterministic and probabilistic hazard assessments indicated substantial non-carcinogenic hazard from tap water exposure, particularly among toddlers (median hazard quotient [HQ] = 2.00, with 99.1% classified as medium hazard. Children exhibited comparable hazard levels, while adolescents and adults had lower hazard levels. In contrast, RO-treated water was associated with negligible hazard across all age groups. Sensitivity analysis identified fluoride concentration as the primary determinant of HQ. The estimated burden of fluoride-related dental fluorosis exhibited spatial heterogeneity, with Disability-Adjusted Life Years (DALYs) ranging from 4.39 to 121.22 and population-adjusted rates from 1 to 668 per 1000 population. Areas relying on untreated groundwater experienced the highest burden, whereas populations using RO-treated water showed minimal attributable disease burden. This study provided one of the few integrated assessments combining probabilistic hazard characterization with DALY-based disease burden estimation for fluoride exposure. Given low public awareness of fluorosis, targeted training for healthcare providers and community-based education programs are warranted to support safer water use and reduce long-term fluoride exposure.