The use of models for regulatory purposes requires accurate descriptions of important chemical fate processes, techniques for applying models for specific regulatory issues, techniques for parameterizing the model, and sufficient model distribution and support. Researchers (i.e. model developers), on the other hand, want to conceive more and more complex, sophisticated models in order to better represent the important environmental processes; unfortunately this invariably tends to lead to models with greater data requirements, parameters that are difficult to evaluate, greater expertise needed for application, and greater computational requirements, all of which makes for more difficult model application and use. The development of usable models for both current needs and future regulatory requirements demands that we achieve a balance between these ‘research needs' and ‘user needs'. Software engineering and code development issues can help to establish the needed bridge between research and user needs so that future models can more quickly escape the research arena and satisfy user needs as effective regulatory tools.