These tools were developed as a modeling-based approach to guide sanitation-related policymaking when precedents or the evidence base is thin. They are intended for practitioners interested in adapting the models for their contexts and assessing the potential cost-benefit of the policies. User guides provide overviews of the base models and guidance on adapting them, while the models of country-specific applications aid comprehension. Practitioners interested in adapting the models should use the ‘Sandbox’ versions. The ‘Original’ versions should be used to understand the model and formulae, identify errors made during adaptation, and as a general reference.