Around 92% of the humanity's footprint (WF) relates to the agricultural sector, and a considerable proportion of this is associated with animal farming. In Spain, the swine sector accounts for 11% of agricultural output in economic terms and makes substantial demands on freshwater resources. In this study we estimate the WF of the Spanish pig sector at an average 19.5 billion m3/yr (82% green, 8% blue, 10% grey) over the period 2001–08. During this period the WF increased by 23%, due to growing exports. About half the water needed to produce concentrate feed comes from Spain, with the remaining 50% embodied in imported feedstock products. When comparing the blue and grey WFs of feed production in the source regions with indicators of water scarcity and water pollution, we find that most of the feed produced in Spain, unlike that imported, comes from watersheds where freshwater resources are overexploited. The evaluation of the WF of four different pig production systems shows that pigs raised in extensive systems have the largest WF per tonne of live animal. However, water pollution is a particular problem in industrial systems given the high geographical concentration of animals. The swine sector is one of the largest consumers of natural resources in Spain and should, therefore, be an important focal point in agricultural, environmental and water policies.