Nope. From reservoirs. Man-made reservoirs. Piped to our homes.
It normally can rain between the middle of September to the end of April. Water is collected in the reservoirs during that time. The months when we don't get rain are in our winter. Nothing grows. Just brown earth. Hence all the dust.
Just remember, SA used to be a first world country with all the bells and whistles until around 30 years ago. Not anymore. It's descending into chaos and lots and lots of hungry children together with very rich politicians.