Limited access to piped water infrastructure has made drinking water quality a critical public health concern in many developing countries, including Indonesia. In densely populated urban areas of Greater Jakarta, households within the Ciliwung Watershed continue to rely heavily on groundwater sources that are vulnerable to chemical and microbiological contamination. This study comprehensively assessed drinking water quality, performed a screening-level environmental health risk assessment, and evaluated household awareness and preventive capacity in the Ciliwung Watershed. Water samples were collected from four locations representing upstream, midstream, and downstream sections of the watershed and analyzed for chemical parameters (Mn, NO3-, Fe, and Zn) and microbiological indicators (total coliforms). A screening-level environmental health risk assessment was performed following the US EPA framework, considering ingestion and dermal contact exposure pathways. Household risk perception and vulnerability were evaluated using the Household Water Insecurity Experiences (HWISE) questionnaire. The results showed that levels of Mn, NO3-, and total coliforms exceeded WHO guideline values at multiple sites, with the highest levels observed downstream, indicating cumulative urban influences on groundwater quality. In contrast, Fe and Zn concentrations remained low and within acceptable limits across all sites. Comparative analysis revealed that well water contained significantly higher levels of Mn, NO3-, and total coliforms than piped water, but not levels of Fe and Zn. Although contaminant concentrations were generally lower in piped water, ingestion remained the dominant pathway of potential health risk concern. While households demonstrated high awareness of water-related risks, preventive capacity differed between well-water and piped-water users. These findings underscore the need for integrated interventions combining risk communication, improved water quality monitoring, and expanded access to safe water in urban watershed settings. © 2026