Once upon a time, water coolers were once simple devices that dispensed water, but new water cooler technology has brought on many changes. The water coolers today still dispense water, but can work with either water bottles or bottle-fed systems, or by being directly connected to the main water source, also known as plumbed-in systems. Modern water coolers can also filter the water if needed, and provide cooled and heated water on demand. These new water coolers are capable of providing many more years of trouble-free usage and require very little maintenance when compared to the older technology.