Population growth and the expansion of human activities are expected to increase by 55% the demand for water resources in the next 35 years. This demand expansion, associated to expected changes in climatic events, highlights the need to better monitor and manage water resources to ensure its long-term provision. We investigated the effects of land cover and precipitation on the quantity and quality (turbidity and dissolved soil) of water delivered to rivers in São Paulo state, Brazil. We analyzed water quality and quantity data from 2000 to 2015 and modelled these variables as a function of the following covariates: percentage of different land cover types (forest, silviculture, sugarcane, pasture and urban), accumulated precipitation before sample collection, MODIS-Enhanced Vegetation Index (EVI), dominant soil class and watershed area. In all our models, EVI was an important predictor of water quality and quantity. Although we detected a negative effect of forest cover on turbidity, there is a positive and stronger effect of agricultural EVI, relative to forest cover, increasing turbidity. These results suggest that reducing sediment inputs into rivers will require both forest conservation and soil protection in agricultural lands. The extent of forest cover and forest EVI were negatively associated with variation in river levels, suggesting that high vegetation structure/biomass stabilizes water flow in these rivers. We conclude that high temporal resolution EVI can help understand the effect of land cover on water provision. Finally, it is essential to protect and increase forest cover to ensure the stability of water provision.