An estimated runtime is not a watering schedule
The target depth is your input. Local conditions decide whether that target is appropriate.
Choose the target before calculating
Ask your water utility or local extension service about plants, soil, rainfall and current restrictions. EPA WaterSense directs readers to local guidance. Our worksheet deliberately leaves the target field empty until you choose it; it does not prescribe a national weekly total.
Understand the scaling assumption
If the same setup averages 0.25 inches in 15 minutes, reaching an average 0.5 inches at that rate would take 30 minutes. This arithmetic assumes an unchanged rate. It is an estimate for the sampled area, not a guarantee that every position receives the target.
Watch the ground, not only the clock
EPA advises stopping when water pools and discusses cycle-and-soak approaches for conditions where application is too rapid. Consult the local source appropriate to your landscape. A calculated continuous duration is not permission to ignore runoff, restrictions or changing weather.
Sources and exact models
- EPA WaterSense · Watering tips ↗Primary source reviewed October 26, 2026