You are correct that South Africa is becoming drier and drier and drought conditions are going to become a permanent feature in our lives in the future so investing in a rain water harvesting system is a great idea. Just 11 mm of rainfall produces 1000 litres of harvested rainwater for every 100 sq. metres of roof area so depending on the size of your home you can harvest a significant amount of water. Rainwater harvesting systems come in a variety of shapes and sizes and can be installed by you or for more sophisticated systems you use a specialist. I’d recommend speaking to a specialist to understand how many tanks you need to serve your needs and what the payback period would be.