Public infrastructure decisions affect many stakeholders with various benefits and costs. For public decisions, it is crucial that decision-making processes and outcomes are fair. Fairness concepts have rarely been explored in public infrastructure planning. We close this gap for a global issue of growing importance: replacing sewer-based, centralized by decentralized wastewater systems. We empirically study fairness principles in this policy-relevant context, and identify possible influencing factors in a representative online survey of 472 Swiss German residents. In a transition phase, innovative, decentralized pilot wastewater systems are installed in households. We designed two vignettes for this context to test the adhesion to principles of distributive justice—equality, equity, and need—at individual and community levels. A third vignette tests procedural justice with increasing fulfilment of fair process criteria. The results confirm our hypotheses: equity is perceived as fairer than equality at individual and collective levels. Contrary to expectations and literature, need is perceived as even fairer than equity. Procedural justice results confirm literature, e.g., the majority (92%) of respondents deems a policy fair that includes them in decision-making. Only few demographic and explanatory factors are significantly correlated with respondents’ fairness perceptions. Although unexpected, this is positive, implying that introducing decentralized wastewater technology can be designed for the entire population independent of characteristics of individuals. Generally, our results confirm literature: fairness perceptions depend on the circumstances. Hence, they should be elicited in the exact application context to be able to enter negotiation processes and provide concrete advice to decision makers.

公共基础设施决策会以各种收益和成本影响许多利益相关者。对于公共决策，至关重要的是决策过程和结果是公平的。在公共基础设施规划中很少探讨公平概念。对于一个日益重要的全球性问题，我们弥合了这一差距：用分散的废水系统代替下水道的集中式系统。我们在这种与政策相关的背景下，对公平原则进行实证研究，并通过对472名瑞士德国居民的代表性在线调查确定可能的影响因素。在过渡阶段，将在家庭中安装创新的分散式中试废水系统。我们针对这种情况设计了两个小插曲，以测试在个人和社区层面对分配正义原则（平等，公平和需求）的遵守情况。第三个小插图通过公平过程标准的日益满足来测试程序正义。结果证实了我们的假设：在个人和集体层面，公平被认为比平等公平。与期望和文献相反，需求被认为比公平还公平。程序正义的结果证实了文献，例如，大多数（92％）的受访者认为政策性公平会将他们纳入决策范围。只有很少的人口统计学和解释性因素与受访者的公平感显着相关。尽管出乎意料，但这是积极的，这意味着可以为整个人口设计引入分散式废水技术，而不受个人特征的影响。一般而言，我们的结果证实了文献：对公平的看法取决于具体情况。因此，