What is the primary purpose of an irrigation check valve?

• A. Filter debris from the water.
• B. Regulate system pressure.
• C. Prevent backflow to protect the water supply.
• D. Store water for peak demand.

Answer: (C)

The primary purpose is to stop water from flowing backward in the irrigation system to protect the public water supply. When zones shut off or pressure drops, water from downstream parts can be siphoned back toward the main supply, potentially pulling contaminants with it. A check valve creates a one-way path, allowing flow toward the sprinklers but preventing reverse flow. This helps ensure that irrigation water cannot contaminate the potable water source. It’s different from filtering debris, which is for removing particles; from regulating pressure, which is handled by a pressure regulator; and from storing water for peak demand, which requires a storage vessel. In many places, backflow prevention is required, and a check valve is a common component used to meet that need, though local codes may call for additional devices for full protection.