Sokhela Gida, 20, of Port Shepstone, pleaded guilty to three rapes and other crimes.
Judge Rishi Seegobin handed down two life sentences for raping a paralysed woman and her 15-year-old daughter in January 2011.
He was sentenced to 10 years imprisonment for breaking into their house, 10 years for raping a 22-year-old woman in August 2010, and five years for assaulting one of the women.
All the sentences would run concurrently with the life sentences.
Seegobin said Gida was well on the way to becoming a serial rapist and it was only a matter of time before he resorted to murder.
In passing sentence the judge said the actions of men who committed depraved sexual acts to satisfy their wanton lust would not be tolerated.
The raped mother and daughter still suffered severe psychological trauma and had to undergo preventive treatment for possible HIV infection.
The girl’s schoolwork suffered after her ordeal and she had emotional problems, such as being afraid of men, including members of her family.