Why is a backflow preventer often required in sprinkler systems?

• A. To prevent backflow into the public water supply (back-siphonage).
• B. To improve water clarity in the system.
• C. To increase overall water pressure in the city supply.
• D. To enable faster drainage during maintenance.

Answer: (A)

Backflow prevention is about protecting the clean potable water supply from contamination due to reverse flow. In sprinkler systems, a drop in pressure or a cross-connection (like hoses or mixed irrigation lines) can create a path for water to flow backward into the drinking water system. A backflow preventer acts as a one-way barrier, allowing water to move toward the sprinkler but stopping it from returning to the public supply. That protection is why codes require these devices.

The other options don’t address contamination risk: backflow preventers don’t improve water clarity, aren’t meant to boost city-wide water pressure, and don’t enable faster drainage during maintenance.