Silent risks of urban water: Reframing water quality as a public health priority in India

Urbanisation in India is a major demographic transition, with nearly one-third of the population living in urban areas and projections approaching 50% by 2050, placing increasing pressure on infrastructure and environmental systems across metropolitan, medium, and smaller cities.¹ Rapid and often unplanned growth has increased water demand while outpacing investments in safe drinking water and sanitation infrastructure. Urban water risks vary substantially across city typologies, with megacities, secondary cities, and informal settlements differing in governance capacity, hydrogeology, industrial exposure, and service continuity, highlighting the importance of recognising urban heterogeneity in public health planning. Many cities depend on a mix of surface and over-exploited groundwater; intermittent supply, ageing infrastructure, and poor maintenance drive reliance on stored water and unregulated borewells, creating pathways for microbial and chemical contamination.² This perspective integrates urban water governance, chemical toxicity, and environmental antimicrobial resistance within a public-health policy framework, explicitly reframing water quality as a measurable determinant of disease prevention rather than an engineering outcome.

Studies from Indian and comparable low and middle-income urban settings indicate that intermittent supply and associated household storage practices are consistently associated with higher faecal contamination and increased diarrhoeal risk, although precise attribution of disease burden varies by context.^3,4 Preventive management of water distribution systems therefore represents a critical public health intervention, as maintaining positive pressure in water mains, ensuring physical separation from sewer lines, rapid leak detection, and systematic replacement of ageing pipes are essential to prevent ingress during low-pressure events, a well-documented mechanism of faecal contamination in intermittent system.³

These vulnerabilities translate into a substantial health burden attributable to unsafe water, sanitation, and hygiene (WaSH) in India.⁵ Global Burden of Disease analyses show unsafe WaSH as a leading environmental risk factor for diarrhoeal morbidity and mortality, particularly among children under five.⁶ Waterborne illnesses such as cholera, typhoid, acute gastroenteritis, viral hepatitis, and routine diarrhoea continue to cause significant morbidity and mortality in urban settings where sewage discharge, runoff, and industrial pollutants compromise water quality. Evidence from Indian environments indicates persistent enteric pathogens linked to endemic and epidemic disease.⁷

Beyond acute infections lies the slower but consequential problem of chronic toxicity. Urban aquifers and peri-urban groundwater increasingly show elevated nitrate, fluoride, arsenic, and industrial pollutants. Nitrate exposure is associated with methemoglobinemia and adverse developmental effects; fluoride causes dental and skeletal fluorosis; and chronic arsenic exposure has been linked to skin lesions, cardiovascular disease, and cancers.^8,9 Heavy metals such as lead, chromium, and cadmium further contribute carcinogenic and non-carcinogenic risks in groundwater and surface sources.¹⁰ These cumulative exposures remain clinically under-recognised but epidemiologically significant, reflecting gaps in groundwater regulation, land-use planning, and industrial enforcement.

A critical but underappreciated public-health dimension is the role of urban water as an environmental reservoir for antimicrobial resistance (AMR). Aquatic environments in India contain antibiotic residues, resistant bacteria, and diverse antibiotic resistance genes (ARGs), reflecting sustained contamination from urban sewage, hospital effluents, and pharmaceutical waste streams. Metagenomic analyses of river sediments impacted by urban waste have detected high levels of transmissible ARGs, including carbapenemases, in rivers flowing through Indian cities, with relative ARG abundance many-fold higher in urban stretches compared to upstream sites.^11,12 Emerging evidence in India indicates increasing resistance among Enterobacterales and other pathogens, illustrating the interface between environmental reservoirs and human health.¹³ While direct causal attribution of environmental AMR exposure to clinical resistance remains limited, converging evidence from environmental detection, biological plausibility, and epidemiological trends supports a contributory role of urban water systems as amplification reservoirs rather than primary drivers of resistance.^12-14 Wastewater surveillance is emerging as an early warning system for pathogens with epidemic potential. Studies show that viruses such as SARS-CoV-2 and others can be detected in wastewater before clinical cases rise, offering critical lead time for public-health action.¹⁴

Insufficient sewage treatment capacity remains a central constraint, with only about 28% of urban wastewater and sewage in India currently treated,^15,16 leaving the majority discharged untreated into surface and groundwater systems. This is compounded by weak enforcement of effluent standards, fragmented institutional responsibilities across water and health sectors, limited accredited laboratory capacity, and underinvestment in continuous, pressurised piped supply, together generating predictable failure modes.¹⁷

These governance gaps interact with social determinants. Households in informal settlements often experience intermittent supply, lack safe connections, rely on stored water or borewells, and have limited access to health services. Surveillance remains largely passive, with under-reporting of outbreaks and limited integration of environmental testing, leaving systems to respond primarily to clinical outcomes rather than upstream risks.^5,18

Urban water policy should prioritise quality assurance, continuous pressurised supply, and contamination prevention over volumetric expansion. Evidence indicates that loss reduction and quality-centred service delivery yield greater health returns than unsafeguarded capacity expansion.^19,20 This policy reorientation does not require new legislation so much as reframing and activating existing instruments as public-health tools. The BIS Drinking Water Standards (IS 10500:2012), the Water (Prevention and Control of Pollution) Act (1974), the National Urban Sanitation Policy (2008), the National Water Policy (2012) and the National Action Plan on AMR collectively provide standards for microbial and chemical safety, pollution control, sanitation coverage, equitable access and recognition of water systems as AMR transmission pathways.

From a public health perspective, however, these frameworks remain predominantly supply and infrastructure-oriented, with limited translation into outcome-driven health protection. Persistent implementation and enforcement gaps, minimal health-sector engagement, and weak integration of water-quality monitoring with disease surveillance constrain their effectiveness. None explicitly mandates routine linkage of drinking-water data with health surveillance, nor requires measurable health-impact indicators as performance benchmarks. Consequently, policy success is often assessed through infrastructure expansion rather than sustained reductions in diarrhoeal disease, chronic toxicity, or antimicrobial resistance. This misalignment represents a critical gap in public-health accountability, through which regulatory weaknesses in groundwater control, land-use planning, and industrial enforcement continue to translate governance deficits into preventable urban health risks.

In the face of these infrastructural and governance constraints, pragmatic, evidence-based public-health interventions can substantially reduce morbidity while longer-term system upgrades proceed. At municipal and programme levels, three linked priorities should be pursued: (i) conversion of intermittent networks to continuous, pressurised piped supply where feasible since continuous service reduces intrusion, limits household storage and lowers exposure to faecal contamination; (ii) sewage treatment capacity must be scaled and modernised, with strict enforcement of industrial and hospital effluent standards to prevent pathogen and chemical loading of surface and groundwater; (iii) decentralised and routine water-quality monitoring, encompassing microbial, chemical and antimicrobial resistance gene surveillance, integrated with syndromic and laboratory-based health surveillance so that environmental signals trigger timely public-health action.

Beyond network-level interventions, source-level pollution prevention, including strict industrial zoning, mandatory pre-treatment of effluents, and regulation of hospital and pharmaceutical discharges, is essential to reduce contaminant loading before pollutants enter urban water systems. Operationalisation of these priorities requires accredited testing, transparent reporting, rapid-response teams, and coordination mechanisms between water utilities and health departments. Success should be measured primarily through sustained declines in diarrhoeal incidence, hospital admissions, contamination events, and antimicrobial resistance gene prevalence, rather than engineering outputs alone.

At household and community levels, short-term protective measures remain essential while system-level fixes are rolled out. These include boiling, filtration, chlorination, safe storage, and targeted behaviour-change communication, especially in high-risk areas. During water scarcity, prolonged storage and reliance on unsafe sources increase infection risk, highlighting the need for risk communication, emergency measures, and provision of safe alternatives.

Interventions should be evaluated using implementation-oriented approaches linking water quality improvements to clinical outcomes. Critically, containment of antimicrobial resistance must integrate WaSH interventions with antibiotic stewardship and environmental controls: wastewater upgrades should aim to reduce antibiotic residues and antimicrobial resistance gene dissemination, and hospital and pharmaceutical effluents must be regulated, monitored, and treated to minimise environmental selection pressure.^18,12

Clinicians should interpret recurrent community diarrhoea, clusters of febrile jaundice, or persistent typhoid as potential indicators of upstream water-system failures and liaise early with public-health authorities. Rising resistance patterns should prompt investigation of environmental sources alongside stewardship efforts. Health administrators must ensure integrated surveillance, accredited testing, and inclusion of WaSH indicators linked to clinical outcomes, with priority for vulnerable populations.

Beyond clinical vigilance, system-level integration is equally critical. Routine urban water-quality data should be systematically shared with health authorities to enable early outbreak detection, informed clinical response, and defined outcome monitoring, including sustained reductions in diarrhoeal incidence, contamination events, and antimicrobial resistance gene trends. Policies should treat water supply and sewage treatment as health-sector investments, embedding health-impact monitoring within urban water programmes.^3,16 Constraints such as limited laboratory capacity, lack of methodological standardisation, inadequate financing, and weak data-governance frameworks must be addressed to translate monitoring into population-level health gains.