[1] The Hennops River starts in Terenure, Kempton Park, and flows in a northerly direction towards Tembisa township.

Insufficient and poorly-maintained sanitation facilities in Tembisa, Ivory Park, Olifantsfontein and Erasmia have turned the river into an open sewer.

The health risk is high for people coming into full or partial contact with water having more than 2000 colony forming units per 100 ml.

[2] Untreated or partially treated sewage also contains high concentrations of phosphate and nitrate, which contribute to the eutrophication problems in Hartbeespoort Dam.

In 2020 the FRESH NGO installed litter traps at Clayville township in Tembisa, and locals were employed to remove the waste which soon accumulated.