How to Determine Gallons of Water Per Hour Needed for a Plant Drip System


When you are planning to install a drip irrigation system, you must use the correct emitters to deliver water to the vegetation. To determine the correct emitters, you need to know the water pressure per hour, expressed as gallons of water per hour (gph). To determine the correct gph, there are simple calculations you can do.

Step 1

Select a bucket to measure water in. Find out how many gallons of water the bucket will hold. This should be listed on the side or underneath of the bucket.

Step 2

Put the bucket underneath a water spigot so water can flow freely from the spigot into the bucket.

Step 3

Open the spigot all the way so the water runs full force. Use a timer to count 30 seconds. Turn off the water. Observe the level of the water to determine the amount of water in the bucket. For example, using a 5-gallon bucket, if you filled the bucket half way, you have 2 1/2 gallons. Convert this to decimals to calculate (2.5 gallons).

Step 4

Use the calculator to divide 60 minutes (1 hour) by 30 seconds; this would be 60 divided by 30 to equal 2.

Step 5

Multiply the gallons of water collected in Step 3 by the result of the calculation in Step 4. Using the example provided, this would be 2.5 gallons multiplied by 2 (2.5 x 2 = 5).

Step 6

Multiply 60 minutes by the total from Step 5. This will give you the total gallons per hour for the water. Using the example, you would multiply 60 by 5 to get a total of 300. This means you need emitters that can operate with a water pressure rate of 300 gph for your drip irrigation system.

Things You'll Need

  • Bucket Timer Water source Pencil and paper Calculator


  • The Drip Store: Calculating Water Requirements
  • Colorado State University Extension: Drip Irrigation for Home Gardens
Keywords: drip irrigation systems, measuring watering needs, water measurement methods

About this Author

Jack S. Waverly is a Pennsylvania-based freelance writer who has written hundreds of articles relating to business, finance, travel, history and health. His current focus is on pets, gardens, personal finance and business management. Waverly has been writing online content professionally since 2007 for various providers and websites.