Celebrating Earth Day: Ferrocement Cisterns For Rainwater Harvesting

By Aundria McMillan Humphrey

For over a decade, the Rotary Club of San Miguel de Allende-Midday has been dedicated to addressing the urgent need for clean and accessible water in rural communities. One of its most impactful projects is the Rain Harvesting System. This initiative has improved water access and empowered local families with skills and knowledge for self-sufficiency.

The rain harvesting system is designed to capture and store rainwater during the wet season, providing a reliable source of clean water for families throughout the year. The system is built directly into homes, where rainwater is channeled from the roof through PVC pipes into a ferrocement cistern. Before collection, the roof undergoes a thorough cleaning to ensure water purity. The stored water is primarily used for drinking and cooking, significantly enhancing the quality of life for participating families.

Each ferrocement cistern has a storage capacity of 12,000 liters, sufficient to supply a household of up to seven people with drinking and cooking water for an entire year. Families receive training on proper maintenance to keep the water clean and fresh, ensuring the system remains sustainable for years to come.

Education plays a crucial role in maintaining the safety and effectiveness of the rain harvesting system. Families are trained in best practices for roof maintenance, cistern cleaning, and the "first flush" technique, which discards the first rainfall to remove contaminants. Additionally, follow-up visits are conducted six months after installation to assess the system’s performance and reinforce good maintenance habits.

The introduction of ferrocement cisterns has brought a profound change to rural communities. Aside from providing a sustainable water source, the project has had far-reaching social and health benefits. Women, many of whom are heads of households, receive hands-on training in construction, learning to mix cement and build cisterns as a team. This empowerment fosters independence and strengthens community ties.

Health improvements have been particularly striking. The availability of safe drinking water has led to a decrease in conditions linked to contaminated groundwater, including dental fluorosis, bone pain, kidney disease, cognitive impairments in children, and chronic headaches. Families that once struggled to access even small amounts of potable water now have a reliable, safe, and sustainable solution.

The need for a safe water solution was first identified in 2008 through an extensive study conducted by Rotary Club members. Their research revealed that municipal efforts and existing NGOs were not adequately addressing the issue of water scarcity in the region. Recognizing the potential of rainwater harvesting, the club partnered with CEDESA, a local organization specializing in water security and rural development. Since launching the initiative in 2009, the Rotary Club of San Miguel de Allende-Midday has been a pioneer in ferrocement cistern construction, investing over $900,000 USD through global grants from The Rotary Foundation. These funds cover construction materials, training, education, monitoring, and follow-up services. To date, nearly 1,500 cisterns have been built, positively impacting thousands of lives.

Despite the project's success, government incentives for rain harvesting remain nonexistent, underscoring the importance of continued Rotary support and community involvement. As the project grows, the focus remains on sustainability, education, and expanding access to more families in need.

The Rain Harvesting System exemplifies the Rotary mission: uniting people with a shared vision to create lasting, positive change. By harnessing the natural resource of rainwater, this initiative not only alleviates water scarcity but also uplifts communities, proving that with the right support, simple solutions can have life-changing impacts.

For more information contact Lee Carter, President, Rotary Club of San Miguel de Allende-Midday. Lee has been integrally involved in the development and management of the Rain Harvesting Water Cisterns (since 2008) and Dry Composting Toilets (since 2018) projects and securing global grants from The Rotary Foundation for these projects. Carla Cadena has been  Project Team Leader for the Rain Harvesting Water Cisterns since 2016. www.rotarysmamidday.org

Aundria McMillan Humphreywww.slowdowngranny.com