Abstract

Singapore's Active, Beautiful, Clean (ABC) Waters Programme integrates flood protection with recreational amenities through canal upgrades across public housing estates. While previous literature identifies a bundled value uplift, this study isolates the protection and amenity channels using a stacked triple-difference design on 157,851 public housing resale transactions. Exploiting cross-sectional variation in flood risk, we estimate a 2.3% differential protection premium for high-risk properties and a -1.4% base treatment effect for low-risk neighbours, yielding a negative aggregate benefit-cost ratio of -0.25. These estimates mask sharp spatial heterogeneity in the net treatment effect: in central, high-value estates, prestige-sensitive buyers assign a -4.5% net discount to high-risk properties near upgraded canals; in peripheral heartlands, pragmatic buyers price a 4.0% net premium. Furthermore, a 2019 government announcement on sea-level vulnerability triggered a structural break in capitalization. Prior to this exogenous shock, the programme's financial impacts were allocated progressively, as lower-wealth households captured a substantial protection premium. Post-2019, as the signal shifted market focus from local protection to systemic climate stigma, this progressive premium evaporated, inverting the programme into a regressive amenity. These findings suggest that as systemic threats become salient, adaptation infrastructure may generate regressive capitalization patterns rather than functioning purely as a protective public good.