A graphical pinch approach for analysis of water footprint constraints on biofuel production systems is presented. The technique is based on the composite curve method which was originally developed for carbon-constrained energy planning, which is extended in this paper based on the underlying similarities of source-sink allocation problems. The pinch analysis approach enables limiting water footprint conditions to be identified, and provides insights that are useful for planning the large-scale cultivation of biofuel crops. An illustrative case study based on the bioethanol program of the Philippines is solved using the proposed approach. (C) 2008 Elsevier Ltd. All rights reserved.