The City of Tshwane has shut down the Temba water treatment plant after partially treated effluent made its way into the Apies River, a statement said on Friday.
The shutdown on Thursday was the result of a lightning strike last Friday which caused a fault at the Rooiwal waste water treatment plant.
As a result, the partially treated effluent ran into the river which feeds Leeukraal Dam.
"The plant is expected to resume operations within the next seven to 10 days, provided the raw water quality has improved," the municipality said.
In the meantime, arrangements have been made with Magalies Water to increase its pumping capacity into the Babelegi reservoir.
Roaming tankers will also supply residents with water until the situation returns to normal.