Food and fuel security in the face of population growth and climate change represent key societal challenges. Extending an arable farm-level bio-economic optimisation model ‘MEETA’ to include dedicated energy crops (DECs) and water metrics, we quantify water use implications and trade-offs between greenhouse gas emissions, net energy and farm profitability. Drawing upon the limited available water use data for arable and energy crops applicable for East Anglia in the UK, six different farm scenarios were investigated. Profit maximisation produces a conventional crop mix, while maximising net energy and minimising greenhouse gas emissions result in crop mixes which impose financial penalties and lower water use in comparison to conventional cropping; average financial impacts of the associated reduced water use under these respective scenarios range from £0.12 to £0.28 per m3 of water. Confidence in these results and work on water use and management more generally would be improved through better data on inter-annual crop-water needs, temporal water availability relationships and water response functions. Water availability for UK crop production is largely perceived to be a non-limiting resource; however climate change predictions demonstrate that availability of water for UK crop production is of increasing concern for both farmers and society as a whole.