Irrigation project: 10 × 8 m rectangular garden
Real scenario: 2.8 bar pressure, 18 L/min flow rate, 2 zones (lawn + drip flower bed), 6 pop-up sprinklers and 8 drippers. Layout, calculations and complete materials list.
Garden starting data
Measurements and characteristics
- Dimensions: 10 m × 8 m (80 m²)
- Shape: regular rectangle
- Lawn: 65 m² (central strip)
- Shrub bed: 15 m² (north side, partial shade)
- Soil type: medium clay
- Lawn exposure: full sun
Measured water data
- Static pressure (tap closed): 2.8 bar
- Dynamic pressure (washing machine running): 2.2 bar
- Maximum flow rate: 10 liters in 33 seconds = 18.2 L/min
- Connection: garden tap on the east side, 40 cm above ground
The dynamic pressure of 2.2 bar is the value used for all subsequent calculations. Estimating 0.6 bar of losses along the pipes and valves, the pressure available at the sprinklers is about 1.6 bar — enough for 4 m sprinklers, which already work well at 1.5 bar.
Zone split (hydrozones)
With different pressure and water needs between lawn and flower bed, two independent zones are created:
- Zone 1 — Lawn: 65 m², rotating pop-up sprinklers, 3–4 times/week in summer, 20–25 min per session.
- Zone 2 — Shrub bed: 15 m², self-compensating drippers, 2 times/week in summer, 30–40 min per session.
The drip zone requires a pressure regulator (1 bar) upstream of the drip line because self-compensating drippers work at 0.5–1.5 bar, and at 2.2 bar mains pressure there's a risk of exceeding the maximum pressure threshold.
Sprinkler layout (Zone 1 — Lawn)
With a 4 m radius and a 10 × 8 m lawn, the head-to-head principle applies: maximum distance between adjacent sprinklers = 4 m.
Layout:
- NE corner: 1 sprinkler 90° (north side + east side)
- NW corner: 1 sprinkler 90° (north side + west side)
- SE corner: 1 sprinkler 90° (south side + east side)
- SW corner: 1 sprinkler 90° (south side + west side)
- Center of north side (5 m from NE): 1 sprinkler 180° (north side facing center)
- Center of south side (5 m from SE): 1 sprinkler 180° (south side facing center)
Zone 1 pipe route
- 25 mm PE main pipe from the tap (east) to the solenoid valve: 2 m
- From the valve, 25 mm PE pipe along the south side: 10 m to the SW corner
- Running up the west side: 8 m to the NW corner
- Along the north side: 5 m to the north center
- 16 mm PE branches to each sprinkler: 6 branches of 0.5–2 m each
Layout (Zone 2 — Drip flower bed)
The 15 m² flower bed on the north side (3 m × 5 m) contains 8 medium shrubs. A 16 mm PE drip line is used with plug-in self-compensating drippers at 2 L/h roughly every 60 cm.
- 16 mm PE pipe from the drip solenoid valve to the flower bed: 3 m
- 1 bar pressure regulator before the flower bed entry
- Drip line around the flower bed perimeter with 8 drippers placed at the base of the shrubs: about 22 m of pipe
- End-of-line cap at the end of the circuit
Circuit calculation: flow check
Zone 1 (lawn): 6 Hunter PGP-ADJ sprinklers with a 4 m radius each consume about 1.8 L/min at 1.5 bar = 10.8 L/min total. With 18 L/min available, the circuit is at 60% of maximum flow: wide margin.
Zone 2 (drip): 8 drippers at 2 L/h = 16 L/h = 0.27 L/min total. Negligible flow; the drip zone's limit is pressure (handled by the regulator), not flow.
The two zones do not run at the same time. The maximum flow used at any moment is that of Zone 1: 10.8 L/min < 18 L/min available.
Complete materials list with indicative prices
| Component | Qty | Indicative price |
|---|---|---|
| Hunter PGP-ADJ rotating pop-up sprinkler (4 m radius, 90° arc) | 4 | €10–15 each |
| Hunter PGP-ADJ rotating pop-up sprinkler (4 m radius, 180° arc) | 2 | €10–15 each |
| Self-compensating dripper 2 L/h on stake | 8 | €1.50–2 each |
| PE 25 mm PN6 pipe (main line) | 28 m | €1.20–1.80/m |
| PE 16 mm PN6 pipe (sprinkler branches) | 18 m | €0.60–0.90/m |
| 25 mm T-fitting (zone branch) | 2 | €2–3 each |
| Reducing T-fitting 25–16 mm (sprinkler outlets) | 6 | €1.50–2 each |
| Sprinkler outlet fitting 16 mm 1/2" | 6 | €1.20–1.80 each |
| PE 16 mm PN6 pipe (drip zone) | 22 m | €0.60/m |
| 1 bar pressure regulator (for drip zone) | 1 | €8–12 |
| 1" 24V solenoid valve (lawn zone) | 1 | €18–25 |
| 3/4" 24V solenoid valve (drip zone) | 1 | €15–20 |
| 2-zone 24V controller with rain sensor | 1 | €35–60 |
| 1" mesh filter (before the valves) | 1 | €5–8 |
| Assorted fittings (elbows, caps, end-line) | kit | €15–25 |
Estimated total materials cost: €220–380. DIY installation: 1–2 days for trenching and laying on 80 m².
Mistakes to avoid in this project
- Don't mix pop-up and drip on the same circuit: Zone 2 always has a separate valve and a dedicated pressure regulator.
- Don't skip the pressure regulator on the drip line: without a regulator, 2.2 bar will ruin the drippers within a few weeks.
- Don't space sprinklers more than 4–5 m apart: in this garden, 5 m is only acceptable with the radius adjusted up to 5 m.
- Don't bury pipes less than 20 cm deep: pipes should sit at 20–25 cm to avoid damage from lawnmowers and frost.
Recommended schedule
- Zone 1 (lawn): Monday, Wednesday, Friday at 5:30 AM — 22 minutes in summer, 12 minutes in spring/fall.
- Zone 2 (drip): Monday and Thursday at 6:00 AM — 35 minutes in summer.
- Rain sensor: 8 mm threshold — blocks both zones if enough rain has fallen.
Generate the project for your garden
These examples show typical scenarios. Use SprinklerMap to calculate a precise layout, pressures and materials list for your real situation.