Colombia's discharge fee system for water effluents is often held up as a model of a well-functioning, economic-incentive pollution control program in a developing country. Yet few objective, up-to-date evaluations of the program have appeared. Based on a variety of primary and secondary evaluative data, this paper finds that that the program has been beset by a number of serious problems including limited implementation in many regions, widespread noncompliance by municipal sewage authorities, and a confused relationship between discharge fees and discharge standards. Nevertheless, in several watersheds, pollution loads dropped significantly after the program was introduced. While proponents claim the incentives that discharge fees created for polluters to cut emissions in a cost-effective manner were responsible for this success, this paper argues that the incentives they created for regulatory authorities to improve permitting, monitoring, and enforcement were at least as important.