Variability of water extraction in the root zone is a difficulty in determining criteria for sensor placement aimed at soil water balance and irrigation management. On the other hand, detailed knowledge on the water extraction variability can be the key point to define criteria for sensor placement and put an end to arbitrary decisions. The objective of this study was: (i) to evaluate the influence of sensor placement in one, two and three-dimensional space on the determination of passion fruit evapotranspiration by the soil water balance method (SWB); (ii) develop a placement criterion for soil water sensor (SWS) installation to monitor soil water content (θ) for determining SWB with precision and accuracy close to obtained in a lysimeter-grown passion fruit plant. Passion fruit was cultivated in a protected environment and its evapotranspiration (ETc) was measured by a weighing lysimeter installed in the center of the orchard, using a weighing platform. Inside the lysimeters, 32 TDR sensors were arranged in different positions in order to form one (1D), two (2D) and three-dimensional (3D) monitoring of θ in the root zone. ETc determined by SWB in 2D/3D was similar to the ETc determined by lysimetry. It possible to identify a specific location that can represent the average water extraction within the wet bulb zone or in the root zone, for placing or actuating sensors for irrigation management. In the specific case of this experiment, for example, it was found that the installation of a single probe between 0 and 0.3 m depth and at 0.10 m distance from the dripper allowed obtaining ETc values close to those obtained by weighing lysimeter. The results of this study represent another step in the search for developing general criteria for SWS positioning, which is particularly useful and necessary to make drip irrigation management accurate. However, considering that the study was carried out under a highly controlled condition, with a specific crop, cultivated in a protected environment, with a consistent irrigation management criterium, future studies are necessary for the implementation of generalist criteria.