The grandmother of a four-year-old boy who drowned in a sewer system on Sunday has detailed how the family and neighbours waited hours for someone to retrieve him from the deep hole.

Gordon "Tsontso" Ribane drowned on Sunday just outside the Sejankabo Secondary School yard in Mocoseng village, Mahikeng.

Tsontso's grandmother, Salamina Makaudi, said the boy was playing with his cousins aged five and nine in the yard before they disappeared. Makaudi said she only realised about 1pm that they were missing.

"I went outside to look for him and while I was there, his cousins came to inform me that he fell into the water. How he got there, I honestly do not know. The children told me that they heard him scream while they were playing. I had told him not to go out," Makaudi said. She said she immediately rushed to the scene.

"I shouted at the mouth of the hole, saying Tsontso, Tsontso [there was no response]. I then screamed and people came. I took off my shoes and told them I'm going in to get my grandson. They refused," she said.

Makaudi said residents tried to measure the depth of the system and found that it could be about 15m deep.

She said the fire brigade was called to the scene and none of them were willing to go down the hole. Police also came but they too were too scared of the hole, Makaudi alleged.

"Both the police and the fire brigade did not go in... My grandchild was finally retrieved by one of the residents. He tied a rope around his waist, used a rod to test the waters. He searched inside and saw my grandchild's hand in the water," Makaudi said.

Tsontso's body was retrieved from the water at 8.30pm.

"We are all traumatised as a family. We need counseling. The mother of the child is really in a bad state. This has hit everyone hard," Makaudi said.

North West education MEC Mmaphefo Matsemela said that she was shocked at the death of the child.

"As a department we are very much saddened by this horrific incident of a child who died within our school premises. We never thought that such an incident could happen during the lockdown period wherein everyone is expected to stay at home. We wish to convey our heartfelt condolences to the family of the deceased child, including the community of Mocoseng," said Matsemela.

Efforts to get comment from the police were unsuccessful.