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Helpful Worksheets & Irrigation Equations

Sprinkler System And Irrigation Basics

Having a hard time figuring out how to measure a slope or calculating how many zones you need? Not a problem, below are some helpful tools to help you figure it out.

Determine the Percentage of Slope

Divide the measure of height by the measure of the length and multiply by 100.

Example above: 2 divided by 14 times 100 = 14.3%

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Graph Paper

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Irrigation
Checklist

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Timer to Valve Wire Sizing Chart

Gauge	Maximum Distance
18	1000 ft
14	1450 ft
10	1750 ft
10	1750 ft

Valve Inlet Size

Size of Inlet	Gallons Per Minute (GPM)
3/4"	> 0-10
1"	> 10-20
1 1/2"	> 20-30
2"	> 30-150

PVC Pipe / Schedule 40

PVC Pipe / Class 200

Max GPM Flow	Pipe Size	Valve Size	Max GPM Flow	Pipe Size	Valve Size
> 0-4	1/2"	1/2"	> 0-6	1/2"	3/4"
> 4-8	3/4"	3/4"	> 6-10	3/4"	3/4"
> 8-12	1"	1"	> 10-16	1"	1"
> 12-22	1 1/4"	1"	> 16-26	1 1/4"	1"
> 22-30	1 1/2"	1 1/2"	> 26-35	1 1/2"	1 1/2"
> 30-50	2"	2"	> 35-55	2"	2"
Use this chart to size your pipe according to GPM needed for each zone.

PVC Pipe / Class 125

Poly Pipe / Galvanized Pipe

Max GPM Flow	Pipe Size	Valve Size	Max GPM Flow	Pipe Size	Valve Size
-	-	-	> 0-4	1/2"	1/2"
>0-10	3/4"	3/4"	> 4-8	3/4"	3/4"
>10-15	1"	1"	> 8-12	1"	1"
>15-24	1 1/4"	1"	>12-22	1 1/4"	1 1/4"
-	-	-	> 22-30	1 1/2"	1 1/2"
-	-	-	> 35-50	2"	2"
Use this chart to size your pipe according to GPM needed for each zone.