precipitation rate (mm/hr)
target application depth
Perth sandy soils
Most Perth suburbs sit on deep sand. Apply 6–10mm per session — more than this drains below the root zone before plants can use it.
Two-day roster
Under Water Corporation restrictions, most Perth properties water twice a week. Use the schedule above to split your weekly total across both days.
Cycle and soak
If your run time exceeds 15 minutes and you have a high PR system, split it into two cycles with a 30–60 min soak break to prevent runoff.
Seasonal adjustment
Perth summers need 2× the run time of winter. Reduce by 30–50% in May–August, or use a controller with seasonal adjust.
How long should I run my sprinklers?
What's the formula?
Run time (minutes) = (target depth in mm ÷ precipitation rate in mm/hr) × 60. So if your system runs at 14mm/hr and you want to apply 10mm, you need (10 ÷ 14) × 60 = 43 minutes. Don't know your precipitation rate? Use our precipitation rate calculator first.
How much water does Perth lawn actually need?
Most Perth lawn on sandy soil needs 6–10mm per session, two days per week in summer. That's 12–20mm per week. Overwatering on sand is just as harmful as underwatering — the excess drains below the root zone and is wasted.
What is cycle and soak?
Cycle and soak means splitting a single long run time into two shorter cycles with a rest period in between. This gives water time to infiltrate before more is applied, reducing runoff. It's most useful for high precipitation rate systems (above 18mm/hr) or compacted soils.
Why does my lawn look dry even after watering?
On hydrophobic sandy soils (common in Perth), water can bead off the surface rather than penetrating. A soil wetting agent applied each spring dramatically improves infiltration. If the problem persists, your run time may simply be too short or your heads may have coverage gaps.