The government has announced a multimillion-rand plan to drain the poisonous and acidic water out of Johannesburg's underground mines to prevent it from flooding and spilling into streets.

Although she couldn't provide details, Water Affairs Minister Buyelwa Sonjica said the plans included the building of a pump station next year to drain the water emanating from mines under the city.

In March, The Times reported warnings by scientists and geologists that should the levels of acid mine drainage be left unchecked, it would rise to the surface in two years and corrode the foundations of buildings and other infrastructure, damaging their structural integrity.

Water Affairs regional director Marius Keet said one of the options available to the department would be to locate the pump station at the East Rand Proprietary Mines in Boksburg, east of the city.

"Our estimate is that the pump will cost about R185-million. Water will be partially treated and discharged into the Klip River, which is a tributary of the Vaal River. It will take about one year to design and build the pump," he said.

Keet said acid mine drainage in the Johannesburg region, known as the Central Basin, was within 500m of the surface, and rising at a rate of 0.35m per day. "Something has to be done," he said.

He said the toxic water would become a crisis should it rise to about 150m from the surface.

Sonjica said: "Our immediate priority is to avert the crisis that will be upon us in 17 months. We have to install the pump. It has to happen within 17 months."

Sonjica also announced that the Cabinet had appointed an inter-ministerial committee to address acid mine drainage issues around Gauteng.

"We remain committed to ensuring that the rise in the water table under the Central Basin remains below critical levels, and that there are measures to deal with water already decanting in the Western Basin," Sonjica said.

The Western Basin includes mining areas between Krugersdorp and Randfontein, while the Central Basin stretches from Germiston to Roodepoort, through Johannesburg.

The inter-ministerial committee, Sonjica said, will report back to Cabinet within six weeks.

"Surely government will have to get funding to address issues in the short term," she said, adding that government needed about R218-million to deal with problematic mine water in the short-term.