Determine Water Flow Rate
Four simple steps
How To Measure Flow Rate
The flow rate of your water supply determines how much water you have available for your drip emitters and sprinklers. It is 
commonly measured in Gallons Per Hour (GPH) or Gallons Per Minute (GPM). The greater the rate of flow of water, the more drip emitters you can put on a single watering zone and the more zones you can run from a single irrigation valve. If you are going to add a drip system to your faucet (hose bibb, spigot, hydrant), you'll need a bucket and a stop watch.
To determine the flow rate out of your faucet follow these four steps:
1. Place a 5-gallon bucket under the faucet.
2. Quickly turn on the faucet so that is fully open.
3. Record how many seconds it takes to fill the 5-gallon bucket (gallons per second).
4. Calculate your flow rate to determine Gallons per Hour:
(5 gallons ÷ X seconds) X 60 seconds/minute X 60 minutes/hour = Gallons per Hour (GPH)
Example: If it takes 75 seconds to fill our 5-gallon bucket. The formula is:
(5 gallons ÷ 75 seconds) X 60 seconds/minute X 60 minutes/hour = 240 GPH
Now you know the limit of emitter output for your system. In the example above, you can place a total of 240 1-gph or 480 1/2-gph drip emitters on your system. Note: This is only one factor in designing your system. You also need to consider water pressure and maximum run for mainline tubing. For more details, read our Drip Irrigation Basics & Installation Tutorial.
Control Water Flow to Flower Pots With This Little Valve
1/4" Flow Control Valve inserts into micro tubing
If you use a drip irrigation system to water hanging baskets or flower pots, put a 1/4" flow control valve on each pot. You can reduce the drip irrigation flow or shut it off completely. It's handy if the pot is has not yet been planted and you don't want to water it.
Adjust Water Flow to Garden Boxes With a Flow Control Valve
1/2" Valve fits over mainline tubing
These drip irrigation valves are great when you have garden boxes or drip areas that you may want to turn off seasonally. You can reduce the flow or shut it off completely. 1/2" Flow Control Valves are installed just like a compression coupler.
Here's a list of all the parts discussed in this tutorial.
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$0.25 - $0.60
Volume discounts 1 - 24 $0.60 25 - 99 $0.50 100 - 999 $0.35 1000 + $0.25 Order in Multiples of 5 - Control or shut-off water supply in 1/4" drip irrigation micro tubing. Flow Control Valve easily inserts into 1/4" micro tubing.
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$0.90 - $1.60
Volume discounts 1 - 4 $1.60 5 - 24 $1.35 25 - 99 $1.10 100 + $0.90 For drip irrigation. Control or shut-off water supply in 1/2" drip poly tubing (.700" outer diameter). Black rings indicate 700 fittings.
For a complete listing of all our irrigation products, Irrigation Direct
Last modified: September 21, 2011
