Pesantren — traditional Islamic boarding schools — have educated millions of Indonesian Muslims for centuries. Their curriculum is rooted in classical Islamic texts; their method is a close relationship between teacher (kiai) and student (santri); their character is communal, disciplined, and spiritually serious. They are not, in the conventional imagination, hotbeds of environmental innovation. Pesantren Sumber Barokah in East Java is changing that imagination.
The problem
The villages surrounding Pesantren Sumber Barokah, like thousands of villages across rural Java, faced a persistent clean water problem. The local water table had been contaminated by agricultural runoff, and the municipal supply did not reach the area reliably. Families were buying bottled water at significant expense, or using river water of uncertain safety. Waterborne illness — diarrhoea, typhoid, intestinal infections — was a chronic burden on the community, particularly among children.
The pesantren's kiai, Ustadz Hasan, began incorporating the Quranic concept of khalifah — human beings as stewards of the earth — into his regular teaching. He also, practically, enrolled two of his most technically minded senior students in a solar energy and water purification course run by an NGO partner in Surabaya. They returned with plans. The pesantren community decided to act.
The solution
Working with a university engineering department and a Dutch development organisation, Pesantren Sumber Barokah designed and built a solar-powered water purification system serving the pesantren itself and seven surrounding villages. The system uses photovoltaic panels to power an ultraviolet water treatment unit fed by a borehole reaching below the contaminated water table. Treated water is distributed through a gravity-fed pipe network to standpipes in each village. The entire system was built primarily by santri — the students themselves, learning engineering alongside Quran memorisation — and was completed in 2021.
The results were immediate and measurable. A community health survey conducted six months after the system came online showed a 61 percent reduction in reported waterborne illness cases across the seven served villages. The cost to participating families — who contribute a small monthly fee to a maintenance fund managed by the pesantren — is a fraction of what they previously spent on bottled water.
Faith and technology
What Ustadz Hasan insists upon is the theological continuity between the pesantren's traditional learning and its new environmental work. 'We have always taught that the earth is a trust from Allah,' he says. 'The solar panels are new. The obligation to protect what Allah has given us is fourteen centuries old.' His students — who are simultaneously memorising the Quran and learning to maintain a solar water purification system — seem to experience no contradiction between the two. Both, they say, are acts of worship.
There is a reward for serving any living being.
Growing the network
The model is spreading. Indonesia's Ministry of Religious Affairs has included the Sumber Barokah project in a national programme to replicate community water and energy solutions through pesantren networks. As of 2025, eleven further pesantren across Java, Lombok, and South Sulawesi have implemented similar systems, collectively serving over 40 villages and 120,000 people. The students who built the first system have become trainers for the next wave — a chain of knowledge and care passing from one Islamic community to the next, one village at a time.