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Find Your Perfect System Size
Get the right setup from the start. Before you design your sprinkler system, you need to know how much water you've got to work with. Think of it as your watering budget—and once you've got these numbers, you can plug them right into our free Online Sprinkler System Designer at design.orbitonline.com to create your custom system plan.
Using city water? Follow these quick steps. Using a well or lake? Your pump specs will tell you everything you need.
Check Your Water Pressure (PSI)
Grab a pressure gauge and attach it to the outdoor faucet closest to your water meter. Make sure no water is running anywhere in the house, then turn on the faucet and note the reading. This is your static pressure.
Write this number down on a piece of paper.
Pro tip: Find one with Female Hose Threads.
Find Your Water Volume (GPM)
You need one of two quick measurements:
Water meter size: Check the meter body for a stamped size (usually ⅝", ¾", or 1"). No meter? Just measure your service line instead.
Service line size: Wrap a string around the pipe from the street to your house, then measure that string. Use the chart below to convert to pipe size.
String Length to Pipe Size
| Service Line Size | ||||||
| Approx. String Length |
2¾" | 3¼" | 3½" | 4⅛" | 4⅜" | 5¼" |
| Copper Pipe | ¾" | 1" | 1¼" | |||
| Galvanized Pipe | ¾" | 1" | 1¼" | |||
| PVC Pipe Size | ¾" | 1" | 1¼" | |||
Write these numbers down too!
Your System Design Capacity
Use the chart below to find your max GPM and working pressure. These numbers are your system's sweet spot - stay within them to avoid poor performance or damage.
How to use the System Design Chart
Using the Water meter or Service line size on the side, follow them across and match with your static PSI along the top. If you only have a service line, use the 1-inch water meter to find you GPM.
For example: a 3/4-inch water meter with a 1-inch service line running at 50 PSI gives you 10 GPM and a 35 PSI working pressure.
Write down your GPM and working PSI for the next step.
System Design Chart
| Sprinkler System Design Capacity | |||||||
| Static Pressure | PSI | 30 | 40 | 50 | 60 | 70 | 80 |
| WATER METER | SERVICE LINE |
MAX GPM |
MAX GPM |
MAX GPM |
MAX GPM |
MAX GPM |
MAX GPM |
| ⅝" | ½" ¾" 1" |
2 4 4 |
4 6 7 |
5 8 8 |
6 8 10 |
7 10 13 |
7 12 15 |
| ¾" | ¾" 1" 1¼" |
4 5 5 |
6 7 12 |
8 10 17 |
9 14 20 |
10 17 22 |
12 20 22 |
| 1" | ¾" 1" 1¼" |
4 5 5 |
7 8 14 |
8 14 24 |
9 18 26 |
12 20 30 |
12 20 34 |
| Working Pressure (PSI) | 25 | 30 | 35 | 45 | 50 | 55 | |
Quick Notes
Copper pipe? Subtract 2 GPM from the chart numbers.
Galvanized pipe? Subtract 5 GPM for new pipe.
These numbers assume 100 feet of standard PVC. The working pressure helps you choose the right sprinkler heads for optimal performance.
Bottom line: Stay within your max GPM and use the working pressure when selecting heads. Your system will thank you with years of reliable watering.
Ready to Design Your System?
Now that you know your water capacity, head over to design.orbitonline.com and use our free Online Sprinkler System Designer. Just plug in your GPM and pressure numbers, draw your yard, and get a complete custom system plan with parts list and installation guide. It's like having a pro designer in your pocket!
