As the number of technologies and programming approaches for improving global sanitation grows, there is an increasing need to evaluate the cost-effectiveness of each so that policy can be driven by informed decisions that consider cost as well as impact. I use data from two different urine-collection programs that were implemented in rural South Africa to model the cost-effectiveness of each in terms of the cost per litre of urine collected and the cost per household, over a range of operational values. One program was based on conditional cash transfers with the aim of increasing toilet use, while the second program was centrally managed and designed to be logistically simple for the municipality. In comparing the results of the two models I find a paradox. Urine that is collected from households by the municipality is less expensive than incentivized urine collection on both a volumetric and household basis, but only at urine collection rates that cannot be achieved without incentives. Conversely, the incentivized collection is more cost effective when the collection rates are low, but at rates that would correspond to very low incentive prices, rendering the incentive scheme useless. My results illustrate the importance of cost-effectiveness analysis as a tool in sanitation programming but I also highlight the need to view the data with a more nuanced approach that considers the complexities of program implementation in poor, rural communities as the mathematical optimal may not correspond to a realistic, or socially desirable one.