Protect the wall behind a kitchen sink?

To protect the wall behind a kitchen sink, consider installing a backsplash made of waterproof materials like tile, stainless steel, or acrylic. Regularly check for any leaks and promptly repair them to prevent water damage. Additionally, using a water-resistant paint can provide an extra layer of protection against moisture and stains. Finally, ensure proper sealing around the sink edges to minimize the risk of water seeping behind the wall.