Current approaches to meeting environmental expectations lack a sound, consistent methodology by which the environmental benefit may be quantified in economic terms, thereby enabling cost benefit/cost ratios to be determined and included in the decision-making process. This is being addressed in the United Kingdom through a programme of collaborative research involving the Department of the Environment, the Water Services Association and the Environmental and Economic Regulators. An Interim Benefit Assessment Manual has been produced and is being evaluated by case studies, reporting in 1995 with a revised version of the manual planned to be available in 1996.