Attach drip irrigation systems to your existing outdoor water spigot.

How to Figure Gallons Per Hour in Drip Irrigation

by Mary Lougee

Home drip irrigation systems are simple to install and require no trenching as a sprinkler system does. Drip irrigation applies water slowly to the root zones of plants and trees. This process can save up to 50 percent on your irrigation costs over more-inefficient sprinklers. Plant foliage stays dry in this irrigation system, reducing fungal diseases by applying a precise amount of water to each plant or tree. When installing a drip irrigation system, you must determine how many gallons per hour your water spigot will support.

Place a 5-gallon bucket directly underneath a water spigot spout. Remove any garden hoses connected to the spigot.

Hold a watch with a second hand or a stopwatch in one hand. Turn the spigot handle fully counterclockwise as quickly as possible and immediately start a stopwatch timer or watch the second hand on a watch.

As soon as the bucket is full, stop the stopwatch or note the numbers of seconds on the watch that it took to fill the bucket. Turn the water spigot clockwise to turn it off.

Divide the bucket size by the seconds it takes to fill up, and multiply that number times 3600 seconds -- the number of seconds in an hour -- to determine gallons per hour of water flow. For example, a 5-gallon bucket divided by 240 seconds, times 3600 seconds, equals 75 gallons per hour.

Multiply your flow rate per hour times 0.75 for your maximum flow rate. This total is 75 percent of your actual flow rate and is the largest amount of water available for one drip irrigation zone. Colorado State University Extension suggests dedicating an area, or zone, of your garden to drip irrigation instead of mixing drip irrigation and sprinkler systems.

Items you will need

  • 5-gallon bucket
  • Watch or stopwatch
  • Calculator


  • Most modern-day cell phones have a stopwatch feature on them.
  • Install drip emitters that add up to equal or less than your maximum flow rate from the spigot.
  • Install weed cloth underneath your mainline, securing it with anchors every 3 feet. Add a layer of mulch on top of the mainline to disguise it in your lawn.
  • Put a "Y” connector on the spigot and install your drip irrigation system on one end. This leaves the other end open for use with a garden hose, without the need to disconnect your drip system.

About the Author

Mary Lougee has been writing for over 10 years. She holds a Bachelor's Degree with a major in Management and a double minor in accounting and computer science. She loves writing about careers for busy families as well as family oriented planning, meals and activities for all ages.

Photo Credits

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