In 2015, disastrous floods wreaked havoc in the South Indian city of Chennai and have prompted debates on how to address the impacts of sea-level rise at the coast. In response, coastal environmental publics have emphasized the need to implement coastal regulation zoning rules (CRZ) that govern what construction is permissible at the coast. Courtrooms have become important sites to adjudicate whether buildings adhere to the CRZ rules. In turn, this requires a determination of where the high tide line, marking the end of water and the beginning of dry land, lies and where each coastal zone begins. In this paper, I show that the determination of coastal regulation zone boundaries is not only a task that requires accurate empirical measurement, but also one that is subject to social interpretations of where the land ends and water begins. In other words, coastal boundary-making is the domain of meanings and interpretations. Interdisciplinary scholarship on water has underscored the need to take seriously the materiality of water and the fluidity of boundaries between land and water in deltas, rivers, and shores. In this paper, I use scenes of ethnographic fiction to demonstrate that the material shifts in land and water adjudicated in the court cannot be understood outside of the interpretive and deeply political uncertainties they evoke among coastal publics in Chennai.