Calculators Sprinkler run time
How long should I run my sprinklers?
Nobody can answer that for your system, because it depends entirely on how fast your particular heads put water down. Twenty minutes of testing gives you the real number for the rest of the lawn's life.
10mm is a normal soak for an established lawn. Go higher on sand, lower on clay.
Put five or six straight-sided containers around one station, tuna tins are the classic. Run it for fifteen minutes, measure the depth in each with a ruler, average them, and put that in above.
They will not all match, and that gap matters more than the run time. If one has 8mm and another has 2mm, no run time fixes that. Sort the coverage first.
The longer version
Perth specifics
The sprinkler ban runs 1 June to 31 August every year. It is permanent, not a drought measure, and it covers bore water as well as scheme. Outside those months you get two rostered days based on your house number, so the run time matters more here than somewhere that can water whenever it likes.
Most of Perth is on sand, which drains fast and holds very little. Two shorter soaks usually beat one long one, because the excess on a long run is past the roots before the grass can use it.
Poor coverage
A big spread between containers means blocked, sunken or badly angled heads. You are either overwatering half the lawn to keep the other half alive, or wasting it. Winter is the time to run every station, check for that, and replace the controller battery, so the system works when the ban lifts.
The app does this and keeps score
This gives you a run time for one station. The lawn app holds your lawn's details so you never re-enter them, and it tracks the nitrogen you have already put down this year so later doses shrink instead of pushing you over the cap. Free, no account, works offline.