The multiplication
Gallons per run = GPM × minutes × zones. Weekly = per run × runs per week. Run yours in the Water Use Calculator.
What typical systems use
| Scenario | Per run | Per week | Per summer month |
|---|---|---|---|
| One spray zone, 10 GPM, 13 min, 3×/week | 130 gal | 390 gal | ~1,690 gal |
| Four zones on the same schedule | 520 gal | 1,560 gal | ~6,760 gal |
| Four zones, 2×/week overwatering habit | 1,040 gal | 3,120 gal | ~13,500 gal |
A four-zone system easily crosses 20,000 gallons over a season - and the overwatering habit adds another ~10,000. That is where scheduling math pays for itself.
Compare use against budget, not habit
The Water Budget Calculator computes what your landscape actually needs from ET, plant type, area and efficiency. A 2,000 sq ft turf yard at 75% efficiency in a 1.5 in/week ET week needs about 1,330 gallons per week - if your schedule uses 1,560, you have found a 15% leak in time and money.
The biggest reducers, ranked
- Schedule to the calculated need, not a fixed calendar (ET-based).
- Fix leaks and sunken heads - a single cracked lateral can waste hundreds of gallons per run.
- Convert beds to drip: ~90% efficiency vs ~70-75% for sprays.
- Use pressure-regulated, lower-flow nozzles and cycle-and-soak on slopes.