Plan garden zones with accurate demand in minutes. Switch units and compare device mixes quickly. Export results to share with crews and clients instantly.
Enter counts and per-device flow. Use unit selectors for flexibility. The layout adapts: three columns on large screens, two on medium, one on mobile.
Sample scenarios to help you sanity-check your inputs.
| Scenario | Inputs | Design flow (approx.) |
|---|---|---|
| Drip bed | 60 emitters @ 2 gph, simultaneity 100%, safety 10% | 2.20 gpm (8.33 lpm) |
| Mixed shrubs | 30 emitters @ 2 gph, 6 sprayers @ 1.5 gpm, safety 10% | 10.10 gpm (38.23 lpm) |
| Lawn zone | 6 sprinklers @ 3 gpm, safety 10%, velocity limit 5 ft/s | 19.80 gpm (74.95 lpm) |
Values are rounded and assume full simultaneity.
1) Component flow: Q_component = Count × Flow_each (after converting units to a common basis).
2) Total raw flow: Q_raw = Q_emitters + Q_sprayers + Q_sprinklers
3) Simultaneity adjustment: Q_base = Q_raw × (Simultaneity ÷ 100)
4) Design margin: Q_design = Q_base × (1 + Safety ÷ 100)
5) Pipe sizing by velocity: Q = A × v, so A = Q ÷ v and D = √(4A/π).
The pipe size suggestion compares the required inside diameter to typical inside diameters.
Always confirm device flow using manufacturer charts at your intended pressure.
Correct zone flow helps you select a valve and pressure regulator that can pass the required volume without excessive loss. Start with manufacturer-rated device flow at the intended pressure, then multiply by device count. The calculator totals drip, micro-spray, and sprinkler demand and reports a design flow in both gpm and lpm for quick comparison. For drip zones, confirm whether flow is per emitter or per outlet on a line. For sprinklers, use the nozzle and arc setting used on site.
Mixed zones often fail because drip components are specified in hourly units while sprayers are in per-minute units. Converting everything to a single base unit avoids underestimating demand. If you combine emitters with sprayers, check that operating pressures are compatible, or use pressure-compensating drip devices and separate regulators where needed.
Simultaneity represents how much of the installed hardware runs at one time. Set it below 100% for staged watering, multiple manifolds, or cyclic scheduling on steep slopes. Add a safety factor to cover clogging, nozzle wear, small leaks, and supply fluctuations. Many designs use 5–15% depending on water quality and maintenance.
The pipe sizing estimate uses the continuity relation Q = A × v. After converting flow to a consistent time basis, the calculator computes a minimum inside diameter that keeps velocity under your chosen limit. Lower velocities reduce noise and water hammer and can stabilize pressure at far heads. Use the suggested nominal size as a starting point, then confirm friction loss with your pipe chart.
After calculating, compare the design flow to your water source capacity and the pump curve, not only the mainline size. In the field, measure pressure at the valve while the zone runs and confirm uniformity at the farthest device. Exporting CSV and PDF outputs creates a consistent record for crews, inspections, and audits, and future troubleshooting.
Zone flow rate is the total water delivered when a valve runs. It drives valve sizing, pipe sizing, and pressure stability. Accurate demand helps prevent uneven coverage, low pressure at far heads, and pump overload.
It is possible, but it is rarely ideal. Drip and sprinklers often need different pressures and run times. If mixing is unavoidable, use suitable regulation and verify uniformity across all devices.
Use 100% when everything runs together on one valve. Use a lower value only when the zone is intentionally staged, cycled, or split by manifolds that do not operate simultaneously.
Many designers use 5–15%. Lower values require very clean water and consistent maintenance. Higher values can help cover minor leaks, clogged screens, nozzle wear, and seasonal pressure swings.
It limits water velocity using Q = A × v, then calculates the minimum inside diameter needed for your design flow. The suggested nominal size compares that requirement to typical inside diameters.
You may have too many devices on one valve, an aggressive safety factor, or incorrect per-device flow values. Reduce counts per zone, stage operation, or verify flows and pressures from manufacturer charts.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.