JOHANNESBURG - AfriForum has found that over 80 percent of sewage is not being treated properly before entering rivers.
It tested water at 140 treatment plants and found only 19 percent were compliant.
The lobby group is now concerned over the impact this will have on drinking water.
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"We have to remember that we have very limited water resources in Pretoria and any water whether that’s drinking water or sewage water, its all in a cycle of being used as drinking water," said Marais de Vaal.
"If there’s mismanaged of a water treatment plant works for drinking water the danger becomes that our drinking water won't comply with the necessary standards to meet safe human consumption."