WateringDay
Short answer. Spray heads put down roughly 1.5–2 inches of water an hour, rotors about 0.5–1 inch. For about 1 inch a week that is roughly 30–40 minutes a week per spray zone and 60–120 minutes per rotor zone, split across your allowed days. Measure your own zones with a catch-can test, and split long runs into shorter cycles if water starts running off.
Spray heads vs. rotors
| Head type | Typical rate | Time for ½ inch | Time for 1 inch |
|---|---|---|---|
| Spray (pop-up, fixed fan) | about 1.5–2 in/hour | 15–20 min | 30–40 min |
| Rotor (gear-drive) | about 0.5–1 in/hour | 30–60 min | 60–120 min |
| Rotary nozzles (MP-style) | about 0.4–0.6 in/hour | 50–75 min | 100–150 min |
Colorado State University Extension plans with about 1.75 in/hour for spray zones and 0.5 in/hour for rotor zones (Colorado State University Extension — methods to schedule home lawn irrigation). Spray and rotor heads should never share a zone: one area floods while the other stays dry (Garden Style San Antonio (SAWS) — two different heads are not better than one).
Find your real rate: the catch-can test
- Put 4–6 straight-sided cans (tuna cans work) across one zone.
- Run the zone for 15 minutes.
- Average the depth in the cans and multiply by 4 — that's your inches per hour.
- Minutes for your target = target inches ÷ rate × 60. Example: ½ inch at 1.6 in/hour = about 19 minutes.
How much each week
Aim for about 1 inch a week in the heat of summer, rain included, and less in spring and fall — Colorado State uses roughly ¾ inch a week in spring and fall and up to 1½ inches in midsummer (Colorado State University Extension — methods to schedule home lawn irrigation). With one watering day a week, put the whole amount on that day; with two, split it.
Cycle and soak
Clay soil and slopes can't absorb water as fast as spray heads apply it. If water runs onto the sidewalk, split the run into two or three shorter cycles about an hour apart on the same day — Las Vegas recommends three 4-minute cycles for spray-head lawns.
Per-zone limits in some cities
| Where | Limit |
|---|---|
| Los Angeles (LADWP) | One 8-minute cycle per station per watering day, or two 15-minute cycles with water-conserving nozzles |
| Orlando / Orange County | No more than 1 hour per zone per watering day |
| Las Vegas | Recommended: about 12 minutes of spray-head watering per day, in three 4-minute cycles |
Everywhere else the limit is your watering days and hours — check them below.
Find your watering day
Never miss your watering day. The WateringDay app reminds you the evening before and alerts you when your utility changes stage or season.
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