Flush toilets pose challenges such as resource waste, public health, and social justice.To achieve the Sustainable Development Goal of clean water and sanitation for all, it is essential to address the complex issues around toilets and design alternative systems that effectively manage human waste.Inspired by Actor-Network Theory (ANT), this paper presents findings from a design ethnography in eco-villages about composting toilets and sustainable living.We describe three archetypal composting toilet systems and examine how they operate as creative, community-driven infrastructures that mediate human-nature relationships.We reflect on how ANT provides a useful lens for HCI to understand the socio-technical dynamics of alternative sanitation systems.We analyse how composting toilets mediate human-nature relations three interconnected processes: tinkering, linking, and becoming.We discuss the implications of fostering DIY infrastructure practices as a form of transformational creativity in the pursuit of more sustainable futures.

Figure 1: The design study session has three parts.The first task is Uncovering Challenges and Experiences.The second task is Generating Scenarios, which includes Scenario description generation, Scenario image generation.The third task is Backcasting and Provocation.

Ecovillages, communities in which people integrate self-built houses, shared facilities, organic farming, composting, and self-governance into everyday practices, serve as laboratories for ongoing experiments in sustainable living. While topics like sustainability, simple living, and making are well discussed in the HCI community, we aim to investigate what socio-environmental issues are identified in ecovillages and how and with which ethos makers address these issues in their making practices. In this paper, we present findings from an ethnographic investigation around sustainable making by focusing on the endeavours of three ecovillages and highlighting their ethos to draw out lessons for HCI researchers. We discuss the relationship between making practices and sustainability from four aspects: space, material, network, and meaning, and provide lessons and implications for the HCI community.