Analysis of multi-temporal and spatial trends of rainfall in a river basin is an effective tool for water resources management based on delimited hotspots of water scarcity and flooding risks. The present study aims to characterize rainfall distribution patterns in a coastal watershed, Santa Maria da Vitória River Basin–SMVRB (Southeastern, Brazil), based on 42 meteorological stations, using geostatistical approach (i.e., kriging), from 2004 to 2017. Anisotropy effects on rainfall were observed throughout the year and were related to regional/continental climate processes. Trends in rainfall, from 1970 to 2017, were computed using the RClimDex package with eleven climate extreme indices. The results show that rainfall had an irregular distribution and droughts have become more persistent in recent years causing water scarcity to sustain crops and threatening water supply. In the lower basin, where part of the Great Vitória metropolitan area is located, flooding risks increase in the response of intensive short-term rainfall events. Knowledge of rainfall patterns contributes to assure water security and subsidize adaptative responses to extreme hydrological events.