Water reuse and recycling offer substantial potential for savings in petroleum refining, as the water volumes processed are large. Presently, there is a lack of methods to systematically screen and analyze design alternatives using a total systems approach. Such an approach would consider effluent treatment, recycle of treated water and freshwater distribution simultaneously. The paper contributes with a systematic methodology that empowers conceptual engineering and water-pinch [R. Smith, Chemical Process Design and Integration, 2nd ed., John Wiley & Sons, 2005; Y.P. Wang, R. Smith, Wastewater minimization, Chem. Eng. Sci. 49 (7) (1994) 981-1006; Y.P. Wang, R. Smith, Design of distributed effluent treatment systems, Chem. Eng. Sci. 49 (18) (1994) 3127-3145.] with mathematical programming methods. The method focuses on petroleum refineries explaining trade-offs and savings between freshwater costs, wastewater treatment, piping costs and environmental constraints on the discharge. (c) 2006 Elsevier B.V. All rights reserved.