{ "background": "Water treatment infrastructure in Tanzania faces persistent operational risks, yet systematic, longitudinal diagnostics for policy intervention remain underdeveloped. Existing assessments often lack the temporal dimension needed to isolate the efficacy of specific risk mitigation measures.", "purpose and objectives": "This policy analysis develops and applies a panel-data econometric framework to quantify the impact of infrastructural and managerial interventions on the operational risk profile of water treatment systems. It aims to identify the most effective levers for risk reduction to inform national investment and maintenance policy.", "methodology": "A balanced panel dataset of facility-level operational metrics was constructed. The core analysis employs a two-way fixed effects model: $Risk{it} = \\alpha + \\beta1 Intervention{it} + \\mui + \\lambdat + \\epsilon{it}$, where $\\mui$ and $\\lambdat$ denote facility and year fixed effects. Inference is based on cluster-robust standard errors at the regional level.", "findings": "The model indicates that targeted capital refurbishment is associated with a 22% reduction in core operational risk metrics, a finding significant at the 95% confidence level. In contrast, increases in routine operational expenditure alone showed no statistically significant effect without concurrent capital investment.", "conclusion": "Sustained risk reduction in water treatment systems is more effectively driven by periodic, strategic capital upgrades than by marginal increases in routine operational budgets. This underscores a critical policy trade-off between maintenance and renewal funding.", "recommendations": "National water policy should institutionalise a risk-informed asset management strategy, prioritising cyclical capital refurbishment programmes. A dedicated national risk diagnostic fund, informed by panel-data monitoring, should be established to target the most vulnerable facilities.", "key words": "infrastructure risk, panel data, fixed effects, asset management, water security, operational expenditure", "contribution statement": "This study provides the first longitudinal, facility-level econometric evidence isolating the differential impacts of capital and operational expenditures on engineering risk in the country's water