The socio-technical short-term implications of drinking water hoarding on supply reliability

Panic buying during crises, like the initial hoarding of toilet paper amid COVID-19 restrictions, is mainly driven by social and emotional factors influenced by risk perception and social media content. Similarly, unreasonable drinking water hoarding, i.e., simultaneous withdrawal of water by a large number of customers, can influence the performance of water supply systems (WSS). Decreasing performance (e.g., more friction losses and therefore a smaller outflow rate at faucets) can cause a negative feedback loop that might trigger further water hoarding behaviours. This research explores the socio-technical implications of water hoarding in crisis situations within a WSS. An analysis of an Alpine WSS in Austria reveals that up to 40% of households, with a filling rate of 0.1 L/s (bathtub filling), can hoard without performance drop and negative feedback. Beyond this threshold, impacts become noticeable, leading to inadequate water supply for some households, causing disruptions and negative feedback loops. This emphasizes the need for information campaigns to counter false information, preventing emotional triggers. In conclusion, the research highlights the interplay between technical and social factors in crisis water demand management, stressing the importance of informed interventions to mitigate hoarding behaviour and maintain efficient WSS operation.