Decentralized solutions for safe and affordable drinking water access in the slums of NCT Delhi, India

Abstract

ABSTRACT FLOW OF STUDY: PROBLEM → DECENTRALIZED SOLUTION → FIELD EVIDENCE → FINDINGS → POLICY ACTIONS Delhi's rapid urbanization has created informal settlements with scarce piped water. Water Automated Time Machines (Water ATMs) offer a decentralized alternative, but evidence on their performance is limited. This study surveyed 120 households across five slum clusters (premonsoon 2024), tested 22 water samples, and interviewed 21 stakeholders (thematic analysis, κ = 0.82). Water ATMs achieved 100% BIS compliance vs. 40% (borewells) and 60% (tankers) (p = 0.002). Users saved 47% of daily collection time (60 → 32 minutes; Cohen's d = 1.24, p < 0.001). Mean user cost was $0.12/kL. Satisfaction was more strongly determined by distance (ρ = −0.624) and uptime (ρ = +0.543) than by price (ρ = −0.382). Governance fragmentation (85.7%) and maintenance challenges (95.2%) were key sustainability barriers. Policies should ensure ≤200-m walking distance, preventive maintenance, local spares, and a single nodal agency. Water ATMs can complement municipal systems if governance and reliability issues are addressed. This study provides empirical evidence on performance, user experience, and governance for urban water policy in informal settlements.