If you’ve ever noticed a small, oddly shaped copper pipe in your yard topped with a black plastic cap, you might have wondered what it is — and whether it’s essential. That component is called an anti-siphon valve , and it plays a critical role in protecting your home’s clean water supply , especially in Las Vegas homes with irrigation systems. What Is an Anti-Siphon Valve? An anti-siphon valve is a type of backflow prevention device commonly used on landscape irrigation sys