In addition to land conversion and the reduced forest area, tin mining activities in the Pedindang sub-watershed, Bangka Regency, Bangka Belitung Province, Indonesia, are indicated to cause pollution and damage to land and water resources as well as the quality of the Pedindang sub-watershed. Some parameters that are widely used to identify soil degradation are soil organic matter content, soil bulk density, soil porosity, soil capacity to hold water, soil permeability, and soil texture, especially sand. Some parameters that are widely used to assess the occurrence of water pollution are sediment levels, pH, temperature, COD, BOD, and lead levels (Pb). Pollution and damage to land and water systems, generally causes a decrease in the quality of watersheds. Parameters that are often used as an indicator of a decreasing watershed quality are the increase in river discharge maximum pr peak, the decrease in base flow discharge, the increase in river regime coefficients and annual flow coefficients, and the increase in sedimentation or sediment discharge. The purpose of this study is to examine the effects of tin mining activities in the Pedindang sub-watershed on pollution and damage to land and waters as well as the quality of the Pendindang sub-watershed. The guideline used to assess soil quality is the Government Regulation Number 150 in 2000, while Government Regulation Number 82 in 2001 is used as a guideline for assessing water quality. Meanwhile, the River Regime Coefficient (RRC) and Annual Flow Coefficient (AFC) are used to assess the quality of the Pedindang sub-watershed. The results of the study indicate the occurrence of pollution and damage to the soil and water systems. However, the KRS and KRA parameters do not support indication a decline in watershed quality.