Rainwater Harvesting involves storing of rain water for future use. Based on the configuration of the rainwater harvesting system, the water is stored in:
Plastic Tanks
Barrels
Surface Tanks
Underground Water Tanks
Local water bodies
Of these, an underground tank is the most ideal storage option because:
The soil protects the tank from light and heat.
The temperature of water from the underground tank only reaches 6 to 8° C all year round
Due to the darkness and temperature, algae and microorganisms cannot form
This helps ensure consistent water quality. So if fresh rainwater is stored after proper filtration, it will remain the same.