In July 2025, we addressed one of the least glamorous yet most urgent aspects of water access: flushing school toilets at Sin Cheng Primary School in Lào Cai. In this mountainous region, water scarcity is a constant challenge, driven by steep terrain, deforestation, and fragile infrastructure. In such conditions, toilet water is often the first to be sacrificed. At the school, toilets did not flush, sinks were absent, handwashing was impossible, and the stench was overwhelming.

Recognising that most households relied on rainwater but lacked guttering systems, we designed a simple, low-cost rooftop rainwater harvesting system tailored to local materials and terrain. We installed gutters, water tanks, and sinks. To further improve hygiene, we planted insect-repellent bushes, introduced handwashing education through songs and activities, and guided students in making natural soap from local herbs.

This holistic approach — uniting engineering, environmental design, and community education — transformed a neglected sanitation problem into a sustainable solution. Fifty students and twelves staff members directly benefited from this initiative.