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. The schedule above splits your total across both days automatically.
Cycle and soak
If your PR is above 18mm/hr and run time exceeds 15 minutes, split it into two shorter cycles with a 30–45 min break to prevent runoff.
Seasonal adjustment
Perth summers need roughly 2× the run time of winter. Reduce by 30–50% in May–August, or use a controller with a seasonal adjust feature.
How long should I run my sprinklers?
What's the formula?
Run time (minutes) = (target depth in mm ÷ precipitation rate in mm/hr) × 60. If your system runs at 14mm/hr and you want 10mm, that's (10 ÷ 14) × 60 = 43 minutes. Don't know your PR? Use the precipitation rate calculator or run a bucket test.
How much water does Perth lawn need?
Most Perth lawn on sandy soil needs 6–10mm per session, twice a week in summer — around 12–20mm per week total. Overwatering on sand is just as harmful as underwatering since the excess drains straight through the root zone.
What is cycle and soak?
Cycle and soak splits a long run time into two shorter cycles with a rest period in between. It gives water time to infiltrate before more is applied, reducing surface runoff. Most useful for high PR systems (above 18mm/hr) or compacted soils.
Why does my lawn look dry even after watering?
Hydrophobic sandy soils (very common in Perth) can cause water to bead off the surface rather than soaking in. A soil wetting agent applied each spring dramatically improves infiltration. If the problem persists, your run time may be too short or you may have coverage gaps — a bucket test will show you where.