Assessing Urban Water Recycling in Singapore's Public Housing Sector

Thesis Abstract

Urban water security challenges in Singapore’s public housing sector necessitate an integrated assessment of water recycling strategies that align with high-density, high-amenity living environments and Singapore’s national water strategy. This study investigates the feasibility, acceptance, and performance of urban water recycling initiatives within HDB estates, aiming to improve resilience against droughts while maintaining service reliability, affordability, and tenant satisfaction. The specific objectives are (i) to evaluate the technical, economic, and social feasibility of on-site and district-scale recycled water schemes in selected HDB precincts; (ii) to identify drivers and barriers to adoption among residents and housing authorities; (iii) to quantify potential water demand reductions and cost implications under varying scenario assumptions; (iv) to examine governance, policy, and institutional arrangements that govern recycling implementation; and (v) to develop a decision-support framework for prioritising retrofit investments aligned with Singapore’s Four National Taps strategy and Active, Beautiful, Clean, and Green (ABCG) initiatives. The study adopts a mixed-methods, multi-site case study design underpinned by the Technology–Organisation–Environment (TOE) and Diffusion of Innovations theories to explain adoption and performance differences across precincts. The population comprises residents of 12 HDB blocks across four pilot precincts, facility managers from HDB and regulatory agencies, and water utilities staff. A two-stage sampling strategy yields a sample of 600 households for survey data and 40 in-depth interviews with residents, facility managers, engineers, and policymakers. Data collection combines structured questionnaires, semi-structured interviews, site audits, and documentary analysis of project reports, tariffs, and reliability records. Instrument validity is established through expert review and pilot testing, with reliability checks (Cronbach’s alpha > 0.70 for survey scales). For quantitative analysis, descriptive statistics and inferential tests (multivariate regression, ANOVA, and structural equation modelling) will assess relationships among perceived practicality, willingness to pay, and observed performance metrics, while time-series analyses will evaluate water savings under different operational scenarios. Qualitative data will be analyzed using thematic analysis, supported by NVivo coding, to extract patterns related to social acceptance, governance challenges, and risk perceptions. A conceptual model will be tested to illustrate how technical design choices, social readiness, and policy instruments interact to influence adoption outcomes and system performance. Expected findings indicate that well-integrated, low-treatment-requirement recycled water systems can achieve 15–25% reductions in domestic non-potable demand at a cost premium of 8–12% above conventional supply in high-density precincts, with adoption strongly contingent on trust in institutions, perceived health and safety, and visible co-benefits such as reduced urban heat island effects. The study anticipates heterogeneity across precincts driven by differences in housing tenure, demographic profiles, and prior exposure to water reuse information, with governance arrangements and financing models identified as critical enablers or barriers. The contribution to knowledge includes (i) an empirical, context-specific evaluation of urban water recycling within high-density public housing, (ii) a composite decision-support framework integrating technical feasibility, social acceptance, economic viability, and policy alignment, and (iii) context-rich insights into governance mechanisms that can scale recycling solutions in Singapore’s urban built environment. The main conclusion posits that urban water recycling in Singapore’s public housing is technically viable and socially acceptable when embedded within transparent governance, clear health and safety assurances, participatory planning, and affordable tariffs. Recommendations emphasize co-design with residents, phased pilot expansion, enhanced information campaigns to mitigate risk perceptions, and adaptive financing models that reflect actual performance and learning curves observed in pilot precincts.