This discussion paper supplements the 2018 World Bank Global Study on Aligning Institutions and Incentives for Sustainable Water Supply and Sanitation (WSS), which promotes holistic approaches in shaping policies, institutions, and regulation. The paper examines how lower-, lower-middle-, and middle-income countries (LMICs) could implement more effective regulation to deliver sustainable WSS outcomes by considering political, legal, and institutional realities. Rather than importing “best practice” models, experience has emphasized the importance of developing “best fit” regulatory frameworks aligned with policy and institutional frameworks of LMICs. To this end, this discussion paper provides an overview of three regulatory aspects—objectives, forms, and functions—to support practitioners as they consider their own regulatory reform options. It discusses the objectives of water sector regulation in LMICs, types of regulatory arrangements and structures that are being used in LMICs, and instruments and methods that regulators in LMICs use to implement their mandated functions and ends with suggestions on where the WSS community goes from here to better understand the preconditions for effective regulation. This paper does not offer definitive conclusions but rather provides suggestions on the way forward through a phased approach to regulatory reform. Importantly, it sheds light on issues that warrant further investigation to determine the future of WSS regulation in LMICs.