Determining the factors of variation of plant water status at the landscape scale is crucial for mapping or evaluating crop water requirements, crop suitability or climate change impacts over large areas. This paper studies the influence of the spatial variation of watertable fluctuations on vine water status at the scale of a 62 km2 catchment, the Peyne catchment, located in the south of France. Watertable levels and vine water status were monitored over a set of 33 sites, sampling the main soil and landscape units of the study area. An integrated indicator of vineyard water status during the vegetative season, the carbon isotopic discrimination ratio in grapes, was used to estimate the spatial variation of vine water status. On a subset of nine sites, it was compared to the observed minimum predawn leaf water potential over the vegetative season, which confirmed its relevance as an indicator. Variance analysis showed that the spatial variation of watertable levels explained 28% of the variation of the observed values of the carbon isotopic discrimination ratio. It also showed that the explained variance amounted to 40% when the initial soil water storage prior to the vegetative season was taken as an additional predictor. These results point out the need to take into account the variation of local hydrological conditions as imposed by watertables levels when studying the spatial variation of plant water status or soil water balance at the landscape level. © 2007 Elsevier B.V. All rights reserved.