This study aims to evaluate the roles of community forests managed for different purposes on water storages in plants and soils as the basic information for watershed management. Community forests of Karen people in Chiang Mai province, northern Thailand, were divided to conservation (CF) and utilization (UF) forests. These community forests were classified as pine-montane and montane forests. The number of tree species in the CF and the UF was 256 and 132, respectively. Shannon-Wiener Index in the CF (4.5±0.6) was higher than in the UF (3.4±1.0). Forest biomass was higher in the CF (252.4±72.5Mg ha⁻¹) than in the UF (139.7±36.3Mg ha⁻¹). Water amounts contained in biomass of CF in rainy season (on August 17, 2012), winter (on December 29, 2012) and dry season (on April 20, 2013) were 208.2±68.9, 228.5±71.4 and 231.2±70.7m³ ha⁻¹, respectively while those in the UF were 107.1±29.7, 129.0±33.3 and 124.3±33.0m³ ha⁻¹, respectively. More than 90% of water was stored in soil. The maximum capacities of water storage within 2m soil depths of the CF and the UF were 9584 ±934 and 9463 ±233m³ ha⁻¹, respectively. The water storage amounts in soils in rainy season were 73.8% and 79.2% of maximum capacities in the CF and the UF, respectively. In winter, the storages changed to 80.5% and 74.6%, and in dry season they decreased to be 39.5% and 23.7%. Timber harvest in the UF was the main cause of forest degradation and decrease in biomass water storage. The water storage by these community forests can reduce flash flooding and water supply from them is greatly beneficial to the villagers’ livelihood and also to the lower land communities.