Environmental stable and radioisotope data of springs located in Kullu region of Himachal Pradesh are interpreted to identify the recharge source and to understand the recharge mechanism. Identifying the sources of spring recharge and factors affecting the sustainability are critical in this region due to ever increasing freshwater demand to cater the needs of tourism and population growth. The water quality data indicate that spring waters are fresh in nature with low TDS. The stable isotope data of spring water vary from − 9.1 to − 5.0‰ for δ¹⁸O (mean: − 8.2‰) and − 55.6‰ to − 31.8‰ (mean: − 48.6‰) for δ²H. The stable isotope data indicate that springs have direct contact with rainfall and the dominant source is precipitation during western disturbance. No altitude variation is observed in the isotopic content of the measured springs, suggesting a common source/zone for their recharge which needs to be verified with more spatial and temporal data. Environmental tritium data suggests that spring water is modern and the estimated travel times would be less than 50 years from recharge to spring outlets.