A State renowned for being the model of public health in the country and one which has consistently recorded some of the best health indicators nationwide, is now battling recurrent outbreaks of various water-borne diseases such as shigellosis. The irony is stark, for Kerala has demonstrated the responsiveness and resilience of its health system by having a firm grip on a disease as unpredictable and complex as Nipah.

Now, rapid urbanisation and social development on the one side and inadequate attention paid to environmental health, water quality measures, poor sewage and sanitation infrastructure on the other, is threatening to undo the State’s reputation as a beacon of good public health. The explosion of water-borne diseases and zoonotic diseases in the State points to the system’s failure to pay attention to the social and environmental determinants of health.

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Scale of contamination

A look at the outbreaks of Acute Diarrhoeal Diseases (ADD), Hepatitis A, shigellosis and norovirus in recent years gives an indication of the impact of groundwater contamination on people’s health.

Between four to five lakh cases of ADD are reported every year in the State. Since the past two decades, Kerala has also been experiencing several large and small Hepatitis A outbreaks. In 2025, the State reported 31,536 cases and 82 deaths due to Hep A. This year too, as of June 15, close to 9,000 cases and 25 confirmed deaths have been reported.

Amoebic meningoencephalitis, which has also emerged as a significant public health problem in Kerala, is being linked to the faecal contamination in domestic wells, in which free-living amoeba thrive. This infection has claimed the highest number of lives in the State, with 134 cases and 34 deaths reported as of June 15 this year.

Various studies have reported that groundwater resources in the State have been under increasing stress, with 62% of the population depending on ground water from close to 7 million wells.

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Lack of sewage system

As of 2025, Kerala has less than 6% proper sewerage network coverage, with most major cities having virtually no household sewage collection systems. The CAG’s 2025 report stated that at the closure of the AMRUT Mission, a Central initiative aimed at ensuring universal access to safe water and reliable sewerage connections across urban areas, Kerala’s overall achievement was just 11.25% and only 0.13% households got sewerage connections.

While Kerala does have high sanitation coverage with a significant proportion of households relying on septic tanks or on-site sanitation systems, these septic tanks are poorly designed and located close to domestic wells which lead to groundwater contamination. The fact that Kerala is one of the most densely populated States with small landholdings and houses situated close to each other aggravates the issue. High levels of faecal contamination have been reported in over 70% of the open wells in the State by agencies such as the Centre for Water Resources Development and Management. A study in the urban areas of Thiruvananthapuram in 2018 had reported that coliform contamination was prevalent in 73% of wells and that well chlorination and cleaning practices were inadequate.

Recurring outbreaks of Hepatitis A and shigellosis in the State showed that almost all outbreaks had been in rural areas and were linked to the local source of drinking water. Epidemiological investigations have revealed that water for regional supply systems is often pumped into supply lines without adequate chlorination or filtration, and that these lines often run close to sewage drains — any breaks in the pipeline can lead to major contamination.

It is also true that most of the interventions to provide safe drinking water to people lie outside the health sector, demanding coordinated inter-sectoral efforts. Thus, rather than a failure of public health, the current problem of water-borne diseases seems to be the result of the State’s under-investment in establishing proper sewerage networks.

Prevention of water-borne diseases requires long-term investments in urban planning, establishing safe water distribution systems, sewer networks, wastewater treatment plants as well as measures for environmental and water quality surveillance.

maya.c@thehindu.co.in