Which water source typically contains many millions of gallons (liters) of water and may be found on large commercial or industrial properties?

The correct answer refers to a ground reservoir, which is designed to store significant volumes of water—often many millions of gallons—making it suitable for large commercial or industrial properties. These reservoirs can collect and hold water from various sources, ensuring a reliable supply for fire protection, cooling systems, or even sometimes for operational needs within the industrial or commercial facilities.

Ground reservoirs differ from the other options. For instance, a cistern typically holds water for domestic use but may not have the same capacity as a ground reservoir. Agricultural irrigation systems are specifically designed for water distribution in farming and might not have the storage volume needed for large properties outside agricultural use. Meanwhile, private water storage tanks, while potentially significant in volume, are generally smaller and primarily serve individual residences or small businesses rather than large commercial or industrial sites.