Vinasse is an organic matter and nutrient-rich residue generated during alcohol distillation. However, if applied to crops in excess, it may disturb the complex balance of soil absoption and contaminate groundwater. The goal of this research was to evaluate the effect of a vinasse-distributing pool on the quality of groundwater in a sugarcane field in Pernambuco State, Brazil. Samples were collected from 10 observation wells along three parallel transects around the vinasse-distributing pool. The quality of groundwater as well as the fluvial water of the Ipojuca River was assessed as a control for ocean intrusion. The following parameters were measured: CE, SDT, pH, COD, BOD, NO3-, NO2-, K+, Ca2+, Mg2+, Na+, Cl- and HCO3-. Storing vinasse in the distribution lake disturbed CE, COD and BOD values as well TDS, Cl-, K+, Ca2+ and Mg2+ concentrations in groundwater.