The color of a storage container has multiple purposes, which benefit the RWH system as a whole. The first purpose of color is to protect water quality. A tank that is clear (translucent) allows for sun to penetrate the material and increase the chances of algal growth. Therefore, any clear tank should be painted to be opaque. Besides the growth of algae, the tank color can also affect water temperature. Lighter colored tanks (such as white) reflect solar energy and reduce the water temperature during summer months. (*remember that the tank material itself still needs to be opaque) The best way to balance an opaque tank and increased solar reflection is to paint a black storage container a white color (as seen in this picture above).
The color of the storage container can also be used to improve the apppearance or aesthetics of the RWH system. This may be of concern in public locations or neighborhoods with restrictions. Another way to improve the appearance of a storage container would be to use wooden planks to surround the tank or paint it artistically (as seen below).