Household-level WASH conditions and waterborne diseases among the Vantangiya Scheduled Tribe in India: A micro-scale spatial analysis.

Despite national progress in water, sanitation and hygiene (WASH), substantial disparities persist among Scheduled Tribe (ST) populations, including the Vantangiya community in Gorakhpur, India. This study assessed household-level WASH conditions and their association with waterborne diseases using a complete survey of 621 households across five villages conducted in 2024. Composite WASH indices were developed based on WHO/UNICEF Joint Monitoring Programme (JMP) indicators, including sanitation access, water source and treatment, and handwashing facilities; associations were analysed using Firth's bias-reduced penalized logistic regression alongside household-level spatial analysis. Only 16% of households demonstrated good WASH conditions; 23% lacked toilet access, 32% relied on unimproved water sources, and 52% lacked handwashing facilities. Poor WASH conditions were associated with significantly higher odds of diarrhoea (aOR: 6.41, 95% CI: 2.08-10.11), typhoid (aOR: 8.91, 95% CI: 5.62-14.00), and any waterborne disease (aOR: 5.10, 95% CI: 1.48-9.89), compared with households with good WASH conditions. Spatial analysis identified statistically significant but very weak spatial autocorrelation, indicating localized heterogeneity rather than strong clustering. Notably, many existing toilets were poorly maintained, reflecting measurable behavioural gaps alongside infrastructure deficits. This finding provides context-specific evidence that WASH inequities remain closely linked to household disease risk. Integrating behavioural-focused interventions with infrastructure improvements may enhance effectiveness. Micro-scale spatial assessment further highlights localized high-risk households, supporting targeted, micro-area WASH interventions integrated within frontline public health delivery systems and aligned with Sustainable Development Goal (SDG) 6 in underserved communities.