In general, stainless steel is the most desirable material for outdoor sinks. Its longevity, ease of cleaning, and aesthetic that matches most outdoor appliances make it a relatively easy pick. That being said, copper and granite composite have their positives, too. Copper is antimicrobial, meaning it kills most harmful bacteria on contact. It’s also self-healing in nature because it develops a patina over time, in turn hiding any scratches it may pick up. This green-brown hue adds a touch of warmth to your outdoor space but will ultimately take over the original color of your sink. Granite composite, meanwhile, is the strongest of all these materials and won’t chip, crack, or scratch unless dropped from a considerable height. This composite material comes in a wide variety of finishes, giving outdoor living enthusiasts more design options than copper or stainless steel.