At the production site a few chemicals are added to the lake water to make it clear. The water now looks like clean water. But it is not safe to use just yet. After the water is cleared, it is pumped into big basins with sand in it: sand filters. The water sinks slowly to the bottom. Dirt and other particles will stay on top of and in the sand and the water will go through. The quality of the water improves and undesirable bacteria and viruses are made harmless. MWAUWASA than puts a little chlorine in the filtered water to kill all the diseases in it. The lake water is now drinking water and it is stored in big water tanks.