By Barry Stone
Dear Barry,The home inspector who checked my house recommended anti-siphon valves for the lawn sprinkler system. This came as a surprise, since the system works perfectly. Please tell me the purpose of anti-siphon valves and whether they're truly necessary. -- Lorne
Dear Lorne,
Anti-siphon sprinkler valves are a form of backflow protection. Their purpose is to prevent contaminated water from flowing back into the water supply system of your home. The absence of anti-siphon valves indicates that your irrigation system was installed by someone who lacks adequate plumbing knowledge.
Your irrigation pipes retain standing water long after the system is used. This water can become stagnant, harboring bacteria and other micro-organisms. In the event of back-siphonage, unsanitary water in the irrigation system could contaminate the potable water supply. For this reason, the Uniform Plumbing Code requires that all irrigation lines be equipped with anti-backflow protection.
To ensure health safety, you will need to hire a licensed plumber.
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