How do I Determine Valve Size for a Residential Drip System?

Drip irrigation is the most efficient method of irrigating without wasting water. While sprinkler systems are around 75 to 85 percent efficient, the efficiency of drip systems are typically 90 percent or higher. Drip systems also have other benefits such as easy and inexpensive installation. The highest recommended valves for residential drip systems are called anti-siphon valves. Learning what size anti-siphon valves to install is a simple and easy process, and one of the first steps to installing your very own residential drip-irrigation system.

Five gallon bucket
Stop watch

Instructions

- 1
  Determine the water flow (measured in gallons per minute, or GPM) of the main line or the sprinkler circuit. You do this by filling up a five gallon bucket with water flowing from the main sprinkler line, while timing how many times the bucket fills up in one minute, timed by the stopwatch.
- 2
  Calculate how many gallons of water per minute flows from the main sprinkler line by taking the number of buckets of water filled in the minute and multiplying that number by 5. For example: if you filled up two buckets of water in one minute, then the flow rate would be 2 buckets x 5 gallons each = 10 gallons in one minute. The flow rate would be 10 GPM.
- 3
  Determine whether the flow rate is under or over 13 GPM.
- 4
  Purchase a valve that suits your GPM rate. The necessary valve measurement for a residential drip system is 3/4 inch if the water flow measures 13 GPM or below. If the GPM is above 13 GPM, then the necessary valve measurement is one inch.

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