Casa del Agua's rainwater storage capacity was about 8,000 gallons. Rainwater harvesting systems vary from the simple and inexpensive to the complex and very costly. Directing rainfall to plants located at contoured low points is a very simple rainwater harvesting system. No rain escapes property boundaries. More complex rainwater harvesting systems include water storage.
Rainwater harvesting is an everyman's water augmentation method.
Any container capable of holding rain dripping from roof or patio can be a rainwater harvesting system, but may also breed mosquitoes unless kept covered. A plastic garbage barrel is sufficient. Sturdier and more elegant containers create a more pleasing effect and some are built using backyard technology, such as small ferro cement tanks collecting water at the base of down spouts. The least expensive rainwater storage system uses an above-ground swimming pool, with a lid or cover to reduce evaporation. Rainwater then can be stored for about .07 cents per gallon.