Jakarta – The 13 rivers in the Indonesian capital are turning into a major health hazard as factories and families dump untreated toxic waste into the waterways.

More than 10 years after a programme to clean up Jakarta's rivers was implemented, they remain heavily polluted. An estimated 90 per cent of shallow wells – less than 40 m deep – in the capital have also been polluted by domestic waste.

The worsening water situation in Jakarta and other major cities affects the poor the most, and is noticeable in areas where factories and homes exist side by side. The streets of Semanan, West Jakarta are coloured red, green, blue and black by the overflow from a narrow gutter where factories have dumped untreated industrial waste.

The gutter empties into River Mogot, which also serves as a dump for domestic waste. Its water is thick, black and foul-smelling. Thousands of impoverished families live along the river. They rely on groundwater supplies for drinking, bathing and cooking.

Brackish water also poses a serious problem to people living in coastal areas such as Marunda, a swamp known as "Jakarta's toilet". Potable water is scarce: Residents, mostly fishermen, pay 750 rupiah (13 Singapore cents) for a 15-litre jerrycan of drinking water. Water prices soared to 1,500 rupiah per jerrycan when a reservoir in East Jakarta burst recently.

In coastal North Jakarta, where the water crisis is most severe, only half of the population have access to drinking-water services. The rest buy water from traders. Even then, tap water may be contaminated by heavy metals such as mercury.