Java has less than 10 percent of the country’s water, whereas more than 140 million people live on the island, nearly 60 percent of the country’s population. Kalimantan has 30 percent of Indonesia’s water and only inhabited by six percent of Indonesia’s population. With Java being most heavily populated but having a small percentage of the country’s water, the island is predicted to face a clean water crisis.
The 2015 estimation by Robert Wahyudi Triweko, an expert on engineering and the management of water resources, disclosed that water demand on Java reached 164.672 million cubic meters per year, while the availability of water was only 30.569 million cubic meters per year, leaving a big deficit gap of 134.103 million cubic meters per year.
The renewable water is surface water, but this is often highly polluted and leads households and industry to consume more groundwater. This mostly happen in big cities where dependency on groundwater is widespread.