Field calculator
Drip irrigation run time calculator
Setting a drip zone by guesswork either drowns the plants or starves them. This calculator turns the zone's flow and area into a precipitation rate, then gives the run time to apply a target depth of water. The rate in inches per hour equals the zone flow in gallons per hour times 1.604, divided by the irrigated area in square feet, since one inch of water over one square foot is 0.623 gallons. The run time for a target depth is that depth divided by the rate. Enter the zone flow in GPH, the irrigated area in square feet, and the target depth in inches. Drip applies water slowly and efficiently and goes straight to the root zone, but a long single run on slow-draining soil or a slope can still run off, so split it into shorter cycles with soak time between. Tune the schedule to the plant water need, the soil intake rate, and the weather or evapotranspiration rather than a fixed clock, and confirm against the manufacturer emitter data.
Result
Drip zone run time from the precipitation rate: the rate (inches per hour) = zone flow in GPH × 1.604 / area in square feet (one inch of water over one square foot is 0.623 gallons), and the run time for a target depth = depth / rate. Enter the zone flow in GPH, the irrigated area in square feet, and the target depth in inches. Drip applies water slowly and efficiently; split a long run into cycles so it soaks in instead of running off, and tune the schedule to the plant water need, the soil intake rate, and the weather or ET rather than a fixed clock.
anvilfield.com/calculators/drip-irrigation-runtime-calculator · Free field calculators and FieldOS. A planning estimate, verify against the code, the manufacturer, and the engineer of record.
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Drip run time FAQ
What is drip irrigation?
Drip irrigation is low-volume irrigation that delivers water slowly to the root zone through emitters rated in gallons per hour instead of the gallons per minute a spray head throws. It runs at low pressure under mulch, so a well-built zone reaches around 90 percent application efficiency against spray's 50 to 70 percent.
What pressure does drip irrigation run at?
Drip runs at low pressure, commonly 15 to 30 psi, with most point-source and dripline systems best around 25 to 30 psi and thin drip tape lower at 8 to 15 psi. House pressure runs 50 to 80 psi, so a pressure regulator is required to drop it. Confirm the range against the emitter manufacturer.
Do you need a filter for drip irrigation?
Yes. A filter is required on every drip zone because the emitter passages clog on sand, grit, scale, and organics that the water carries. The common landscape range is 150 to 200 mesh, with 150 for typical drippers and 200 for misters and fine sand. It only works if someone cleans it on schedule.
How long do you run drip irrigation?
Drip runs long and infrequent, often 30 to 90 minutes or more every few days, the opposite of spray. The low application rate needs a long run to soak deep, and the days-between interval lets the soil dry. Set the time from the zone's GPH and area or the gallons each plant needs, not the old spray schedule.
What is a pressure-compensating emitter, and when do you need one?
A pressure-compensating emitter holds a constant flow across a range of inlet pressures using an internal diaphragm. You need PC emitters on any slope, where pressure varies top to bottom, and on long runs, where friction drops pressure toward the end. Without them the low or far emitters flood while the high or near ones starve.