The Kedang Pahu River is one of the main water sources in Damai District, West Kutai Regency, East Kalimantan, which is currently experiencing water quality degradation due to nearby coal mining activities. This decline in water quality has raised concerns among local communities and government agencies due to its potential health and environmental impacts. This study aims to analyze the water quality status of the Kedang Pahu River based on physical, chemical, and biological parameters and to assess the level of water pollution using the Storet method. The research was conducted from March to May 2025, with water samples collected at five different points along the river. The research method used was a quantitative descriptive approach with laboratory testing for water quality parameters including Total Suspended Solids (TSS), temperature, turbidity, pH, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), oil and grease, lead (Pb), and total coliform. The results showed that several parameters, including TSS, BOD, COD, and Pb, exceeded the quality standards set in Government Regulation No. 22 of 2021. The water quality assessment using the Storet method indicated that the Kedang Pahu River falls into the category of "moderately to heavily polluted", with the worst conditions found at sampling points STA3 and STA5. These findings were supported by interviews with the Environmental Agency, sub-district authorities, and residents who reported changes in water quality, increased turbidity, health complaints, and decreased fish catches. The study concludes that coal mining activities have a significant impact on the declining water quality of the Kedang Pahu River. Therefore, more optimal environmental management and stricter supervision of mining activities in the area are urgently needed.