Groundwater forms the backbone of drinking water supply in the Himalayan region, rendering its quality assessment essential for long-term sustainability. This study presents a comprehensive evaluation of groundwater quality in Chamoli and Almora districts of Uttarakhand, employing physico-chemical analysis, heavy metal concentration measurements, and Water Quality Index (WQI) determination. Total 84 samples have been collected out of which 46were collected from Chamoli and 38 samples from Almora ( pre- and post-monsoon seasons in 2021), the parameters that have been analysed are pH, electrical conductivity (EC), total dissolved solids (TDS), major cations and anionsalong with heavy metals such as lead, zinc, manganese, nickel, copper, iron, and chromium, in accordance with “American Public Health Association” APHA (2005) standards and BIS guidelines. Results revealed that groundwater pH in Chamoli ranged from 6.52 to 7.59, with TDS levels between 70 and 602 mg/L, whereas Almora samples showed pH values from 5.92 to 8.21 and TDS from 58 to 426 mg/L; these figures were largely within permissible limits. Concentrations of major cations and anions were moderate, with bicarbonates being the most prevalent anion. Heavy metals were generally present in trace quantities, but a limited number of samples surpassed the desirable thresholds. WQI outcomes demonstrated that groundwater in both districts is predominantly classified as excellent, with Chamoli maintaining consistently high standards throughout both seasons. Almora exhibited minor seasonal variations, with several samples falling into the good quality category. In summary, groundwater in these regions is suitable for drinking and domestic purposes, though occasional instances of elevated heavy metals underscore the necessity for ongoing monitoring and effective management to ensure safe utilization of this vital resource.
