The Jal Jeevan Mission (JJM) is a flagship program launched by the Government of India in August 2019, aimed at providing safe and adequate drinking water to every rural household in the country by 2024. The primary objective of JJM is to provide safe and clean drinking water through functional household tap connections (FHTCs) to all rural households. Bihar is one of the most impoverished areas in the world, with a population of over 1.8 million people living in rural areas. The government of India has launched the Jal Jal Mission in Bihar from August 2019 to 2021. The objective is to improve access to safe and reliable drinking water for millions of rural households through FHTC. The purpose of this study is to assess the impact JJM of improved rural water supply on health outcomes in the state. The results show that the expansion in piped water coverage has significantly reduced the dependence on unsafe water sources and improved the reliability of water supply. Similarly, the fluoride contamination in groundwater of Bihar.. The data show that improved water supply has a significant impact on the incidence of waterborne diseases, child malnutrition, and general health outcomes.