Fast-growing plantations have been expanding in Brazil in the last 50 years, increasing productivity by over 40 m3 / ha in reduced cycles between 5 and 15 years. In the 1990s, environmental warnings about these plantations guided research projects seeking to understand their effects on water and propose forest management actions to minimize them. The assessment of forest management effects on water resources is conducted by long-term experiments in paired catchments. In this study, we present some studies conducted at the hydrological monitoring center of Itatinga Experimental Station, of the University of São Paulo, where hydrological monitoring began in 1987, and currently conduct 4 catchments under different forest management regimes: fast-growing industrial management, long-term forest mosaic management, native forest restoration and long-term coppiced management. Results show that in a site with deep soils and good natural water regulation, main hydrological effects still occur when forest management intensifies, increasing water consumption and making the flow regime vulnerable to intra- and inter-annual seasonality. Regarding water quality, weekly sampling showed little interference of forest management on water chemistry; besides, more intensive management increased the concentration of nutrients in the water. There were no differences in water use in Eucalyptus plantations aged between 10 and 17 years and the use of coppice management had in the first 2 years higher water use than new plantations. The different types of management adopted directly affected the amount of water used, showing that high water demand forest plantations at water deficit regions, water availability is directly controlled by the forest management regime.