Irrigation Guides & References

Practical guides, reference tables and straight answers - every one built on the same math as our calculators and linked to the tool that finishes the job.

Guides

How to Measure Your Water Flow (The Bucket Test)Step-by-step guide to measuring your available water flow with a bucket. Sprinkler Zone Planning BasicsHow to plan sprinkler zones properly: available flow, head flow, hydrozoning by plant type, safety margins and why the last head on the line fails first.

Reference Tables

Pipe Flow Capacity Table (GPM by Pipe Size)Reference table: safe flow capacity in GPM for 3/4 through 3-inch PVC pipe at the recommended 5 ft/s velocity, plus hourly volume. Pipe Friction Loss Table (PSI per 100 ft)Reference table of Hazen-Williams friction loss in PSI per 100 ft for Sch 40 PVC pipe at 5-25 GPM, computed from the standard equation. Sprinkler Spacing Table by Nozzle TypeReference table of typical throw radii and head-to-head spacing for spray heads, MP rotators and gear-drive rotors, plus square vs triangular grid notes. Drip Emitter Flow TableReference table of drip emitter flow rates (GPH), how many emitters each plant type needs, and the weekly gallons that adds up to.

Answers

How Many Sprinkler Heads Per Zone?How many sprinkler heads fit on one zone? The answer depends on measured GPM, head flow and a safety margin - here is the math, with typical numbers. How Long Should Sprinklers Run?How long to run sprinklers depends on application rate and weekly target. How Much Water Does Irrigation Use?Irrigation water use explained in gallons: per run, week, month and year for typical systems, plus how to compare it against a calculated water budget. How Many Zones Do I Need?How many sprinkler zones does your yard need? It comes from area, head spacing and measured water flow - here is the calculation with typical numbers. How Much GPM Does a Sprinkler System Need?A sprinkler system's GPM depends on head count and nozzle type: sprays 1.