The object of research is the economic assessment of buried ductile iron pipelines and technically comparable water-supply pipe materials. Method. A critical synthesis was performed using 112 scientific publications published between 1979 and 2026 and indexed or retrieved through Scopus, Web of Science Core Collection, ScienceDirect, SpringerLink, ASCE Library, IWA Publishing, PubMed, Google Scholar, and eLibrary. Standards were assessed separately. The review compared the objects, data, failure definitions, cost boundaries, time horizons, uncertainty models, validation procedures, and transferability limits of the selected studies. A title-term co-occurrence network was used to reveal the thematic structure of the evidence base. Results. Economic research evolved from deterministic replacement rules based on average break rates to probabilistic life-cycle models that include inspections, imperfect repair, budget constraints, infrastructure interdependence, and service-interruption consequences. Failure-prediction studies provide essential inputs for economic analysis, but their coefficients remain utility-specific because event definitions, censoring, replacement records, climate, soil, and maintenance practices differ among networks. Ductile-iron studies confirm the importance of socket joints, corrosion-protection systems, soil exposure, external loading, and localized corrosion; however, they do not support a universal service-life coefficient or an unconditional economic advantage over polyethylene and steel. Direct comparisons under a common hydraulic function, route, price basis, and analysis horizon remain scarce. Based on the critical synthesis, the author-developed calculation method is formulated. It includes a common functional unit, a risk-adjusted life-cycle cost, threshold values for failure consequences and failure-rate reduction, scenario robustness, minimax regret, and the value of inspection. The method does not predetermine the preferred material and requires local numerical validation.

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