Before/after: wrong layout vs correct head-to-head
Same 10 × 8 m garden. Project A: 4 sprinklers spaced 5–6 m apart. Project B: 6 sprinklers in head-to-head at 4–5 m. The comparison shows dry spots, hidden costs and how to fix it.
The garden
- Dimensions: 10 m × 8 m = 80 m² of lawn
- Pressure available at the sprinklers: 1.8 bar
- Sprinklers: rotating pop-ups with a 4 m radius at 1.8 bar
- Flow per sprinkler: 1.7 L/min
- Available flow: 15 L/min
Project A — 4 widely spaced sprinklers (wrong)
Layout
- NE corner: 90° sprinkler
- NW corner: 90° sprinkler
- SE corner: 90° sprinkler
- SW corner: 90° sprinkler
Distance between adjacent sprinklers: short sides 8 m, long sides 10 m. Maximum radius 4 m: no sprinkler reaches its neighbor.
What happens
The center of the lawn (an area of about 4 × 2 m) receives very little water. The midpoints of the sides receive insufficient water. Estimate: 35–40% of the lawn receives less than 50% of the water it needs.
Visible consequences after 3–4 weeks
- Yellowish streaks at the center of the lawn and at the midpoints of the sides
- The owner increases watering duration — but this causes waterlogging at the corners (already well watered) while the center remains under-watered
- After 2–3 months: permanent turf damage, reseeding needed
Cost of the mistake
- Initial savings: 2 fewer sprinklers = €20–30
- Cost of reseeding and repairing damaged areas: €80–200
- Cost of adding 2 sprinklers after the fact: €60–120 in materials + labor
- Total cost of the mistake: €140–320 — 5 to 10 times the initial savings
Project B — 6 sprinklers in head-to-head (correct)
Layout
- NE corner: 90° sprinkler
- NW corner: 90° sprinkler
- SE corner: 90° sprinkler
- SW corner: 90° sprinkler
- Center of north side (5 m from NE, 5 m from NW): 180° sprinkler
- Center of south side (5 m from SE, 5 m from SW): 180° sprinkler
Distance between sprinklers: short sides 8 m (covered by the corners), long sides 5 m between the corner sprinkler and the center one. With a 4 m radius, 5 m is slightly beyond pure head-to-head, but a 25% overshoot is acceptable for residential gardens.
Resulting coverage
Every point of the lawn receives water from at least 1–2 sprinklers. The estimated distribution uniformity is 75–85%.
Flow check
6 sprinklers × 1.7 L/min = 10.2 L/min total. With 15 L/min available, the circuit is at 68%: wide margin.
Extra cost
2 additional sprinklers: €20–30. 2 T-fittings and 3 m of 16 mm PE pipe: about €8–10. Total: €28–40 more than Project A.
Comparison table
| Feature | Project A (4 sprinklers) | Project B (6 sprinklers) |
|---|---|---|
| Number of sprinklers | 4 | 6 |
| Materials cost | ± €180 | ± €215 (+€35) |
| Maximum distance between sprinklers | 10 m (long sides) | 5 m (long sides) |
| Head-to-head respected? | No | Yes (with 25% margin) |
| Estimated uniform coverage | 60–65% | 78–85% |
| Dry spots after 4 weeks | Yes (center and side midpoints) | No |
| Expected corrective cost (3 years) | €150–300 | €0 |
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.