The amount of water your plants need and when it is needed changes with the weather, length of day, and root depth. By regularly adjusting the watering schedule of your automatic irrigation system (unless you have a smart timer), you can maintain healthy, beautiful plants and avoid wasting water.
In the Pacific Northwest, the watering season typically lasts from April through September. Check this page for advice on programming your sprinkler timer for the upcoming week. Interested in receiving weekly watering advice straight to your inbox? Sign up for the weekly water advice email! From March to October, we’ll send you a short email once per week that includes our watering advice and tips.
Weekly watering advice
Last updated: Thursday, September 3, 2026
Conditions: Recent rain and more mild, possibly rainy days ahead.
Watering recommendation:
- Established high-water-use plants: If the soil is dry beneath the surface, water ½ inch once this week.
- Established deep-rooted plants with deep mulch over the soil: If the soil is dry beneath the surface, water slowly and deeply until the top 6 inches of soil is wet.
Save Water by Planting in the Fall
Late summer and early fall are ideal times to add new plants to your yard since the fall rains do some of the watering! Choose plants that are well-suited to the local climate and get them in the ground before it’s too cold or wet, so roots have time to establish.
After planting, cover the bare soil with a deep layer of arborist woodchip mulch to help retain moisture. When the rain starts, don’t forget to pause or turn off your sprinkler timer! Planting in the fall not only helps establish new plants; it also saves water.
Have specific questions about choosing plants this fall? Reach out to Mark.Guthrie@seattle.gov.
Resources
- Learn more about water-efficient sprinkler systems
- Need some professional assistance? Check out this short list of local certified landscape professionals!
- If you’re interested in learning about supply conditions for Seattle’s regional water system, please visit Water Supply Conditions – Utilities | seattle.gov.
Choosing the right run time for your system
Each watering should apply a ½ inch of water. The application rate of a sprinkler system depends on the water pressure, system design, and system efficiency. Below are some general ranges of typical run times based on the precipitation rate of your sprinkler heads:
| Head Type | Nozzle Description | Run Time* for a ½ inch | If Using Cycles** | |
|---|---|---|---|---|
 | Spray Head | Sprays like a fan | 15-23 minutes | 3 cycles of 5-8 minutes |
 | Rotor Head | Single spray that rotates | 30-75 minutes | 3 cycles of 10-25 minutes |
 | MSMT Head | Multiple single sprays that rotate | 50-75 minutes | 3 cycles of 17-25 minutes |
**Cycling Recommendation: To prevent runoff and ponding in areas with clay soils and/or slopes, divide the run times into three cycles to allow the ground to absorb the water. Additional cycles are created by utilizing more than one start time combined with shorter runtimes.
If you have drip irrigation, follow these guidelines that include how many minutes it takes to water ¼ of an inch:
