Examining the centralization heuristic in Swedish peri-urban and rural wastewater management

• Decision-making heuristics in the water sector in Sweden are explored. • Mixed-method approach including interviews with municipal representatives. • Trend towards centralization in Swedish wastewater management observed. • Decentralization heuristics include different stakeholders, goals and experiences. • Resource constraints, leadership and sustainability goals can drive paradigm shifts. Global questions such as population growth, climate change, eutrophication or resource scarcity challenge the existing wastewater management systems. The centralized wastewater management paradigm is based on a linear model with strong lock-ins where wastewater is collected, treated and disposed. Decentralized and/or alternative local sanitation solutions with focus on resource recovery, such as urine or blackwater separation, could be considered in peri‑urban areas and small communities to increase the recovery of resources and address some of these challenges. This study explores the heuristics in the Swedish wastewater sector, examining the factors influencing municipal decisions when planning or improving sanitation services. Interviews with municipal representatives, along with official statistics and literature, revealed a dominant trend of centralizing systems by decommissioning smaller treatment plants and upgrading larger ones, motivated by system robustness, operational simplicity, cost efficiencies and environmental protection. However, decentralized or resource-recovery systems occasionally arise, driven by strong leadership, sustainability goals and constraints like limited resources. Barriers to these alternatives include economic, legislative factors (lack of requirements), technical (immature technologies, uncertainties), and organizational (lack of initiative, competence and experience) challenges, alongside sectoral inertia and a lack of clear incentives. The findings highlight the dominance of centralization heuristics, possibly because the current conditions do not yet give the practitioners the knowledge, confidence or incentives to make the change, and emphasize the importance of incorporating alternative options into early planning stages. Shared visions, strong drivers and robust leadership can foster a transition toward coexisting centralized and decentralized systems that better address emerging global challenges.