Drivers for the adoption of circular water systems at the building level in a high-income context

Circular water systems at the building level offer potential for sustainable water management. Yet, user acceptance and willingness to pay (WTP) challenge their adoption. This study explores factors shaping acceptance and WTP by surveying 496 respondents on attitudes toward circular water systems and maintenance preferences. In addition, 76 visitors to the KREIS-Haus, a living lab in Switzerland, were surveyed to examine the influence of direct experience with circular water and building practices. Environmental awareness emerged as the most consistent predictor of acceptance of and WTP for circular water systems, while factors including living arrangement, environmental knowledge, dwelling size, and gender were significant in specific contexts. Among the circular practices presented, the use of treated rainwater as potable water, received the highest acceptance. Practices related to the nutrient cycle, such as composting toilets and producing fertiliser from human waste, were less accepted. About half of the respondents were open to participating in gardening (47 %) and minor technical maintenance (50 %), while preferring to outsource compost toilet management. Preferences were shaped by hygiene concerns, perceived effort, and fairness in task distribution. Visiting the KREIS-Haus increased acceptance and WTP, indicating a positive effect of experiential learning. These findings highlight the importance of combining behavioural, organisational, and contextual factors to enhance acceptance. Future research should explore the structure and long-term feasibility of maintenance models and whether stated acceptance leads to actual behavioural change.