CAPE TOWN - The quality of SA's water will continue to deteriorate rapidly unless urgent measures are put in place to manage it better, warns a new report released yesterday by the Council for Scientific and Industrial Research (CSIR).

Population growth and urbanisation, coupled with the "apparent inability of local authorities to treat urban and industrial effluents to the (legal) standards", will heighten SA's water problems, one of the report's contributors, CSIR researcher Dr Paul Oberholster, wrote. Eleven of SA's 19 water management areas were under stress, he subsequently told Business Day.

"There are clear indications from the relatively scanty water quality monitoring data available that the water quality of most South African river and reservoir systems has deteriorated over the last 20 years.

"In some areas - such as the upper and middle reaches of the Vaal River system, the Mgeni River system, the Crocodile River system and the upper and lower reaches of the Olifants River system - the water quality poses serious health risks to humans and livestock that drink the water over many years," he said .

Better water management was essential as the resource was relatively scarce in SA, he said.

Dr Oberholster said eutrophication posed one of the biggest threats to water quality . Problems such as acid mine drainage, while severe, were relatively localised, he said.

Eutrophication is a process in which algae flourish in water that has been polluted with compounds such as nitrates and phosphates.

These pollutants disrupt the usual life forms that live in the water but provide rich nutrients for algae, which clog waterways and treatment plant filters, and in some cases give off deadly cyanide compounds.

"Government, society and the private sector need to work together. Government alone cannot solve the problem," he said.

Dr Oberholster warned that climate change would make the problems worse as higher temperatures would lead to increased rates of evaporation and reduce the volume of water available to a growing population.

Warmer weather would also affect the microbial balance in water supplies, and was likely to lower the quality in rivers and reservoirs. CSIR researcher Kevin Wall , who also contributed to the report, said much of SA's water infrastructure was not in a fit state to deliver reliable, high- quality services.

"The biggest problem we face is that the right people are not in place in the technical and financial departments to operate and maintain the infrastructure properly and to spend the money they have properly," he said in a telephone interview.

SA faced an immense challenge to deal with historic backlogs and provide water services to communities that previously had none, while maintaining infrastructure, Dr Wall said.

In some parts of the country, eradicating the bucket system had made things worse for residents, he said, explaining that while a breakdown in bucket collection caused problems in a relatively confined area, a collapse of water services would cause problems over a much larger region.

"In some Free State settlements, replacement of the bucket system left people with no sanitation at all since the water supply was insufficient to flush their toilets."