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Close up of hand adjusting a irrigation clock

How and when to water your landscape

Your irrigation system is the key to creating a healthy, water-efficient landscape. Find your assigned watering schedule and use the tips in this section to ensure you know how to water and when.

How to set your irrigation clock

Optimize your irrigation system and ensure compliance with watering restrictions by getting to know your irrigation clock.

Manage your clock

You should have an irrigation clock that has a program A, B and C. Using these programs correctly will save water and money.

Program A — Sprinkler irrigation

For each assigned day of watering, water your lawn 3 times a day, 4 minutes each watering. Schedule start times at least one hour apart. See the cycle and soak and sprinkler watering tips pages for more information.

Program B — High-water-use plants on a drip system

Drip irrigation is usually needed less frequently than sprinkler irrigation. How much you water on your designated drip day(s) depends on the type of drip emitter you use, the types of plants you are watering and the condition of the soil.

Program C — Water-efficient plants on a drip system

If your plants appear stressed, check the soil moisture. If the soil is wet, your plants may be over  watered. If the soil is dry, check that all emitters are working. Flush the drip irrigation lines and filters every time you change your irrigation schedule.

Set your clock

You should change your irrigation clock settings each season, both to comply with mandatory watering restrictions and for the health of your landscape.

How to set sprinklers (Program A):

  1. Watering days - Find your "watering days" function and adjust it to ensure it is watering only on your assigned day(s) each season.
  2. Start times - Find your "start times" function and adjust it so you run three sprinkler watering cycles, each about an hour apart. In warm weather, run cycles before sunrise.
  3. Run time - Find your "run time" function and set it to four minutes per cycle.

How to set drip irrigation (Program B):

  1. Watering days - Find your "watering days" function and adjust it to ensure it is watering only on your assigned day(s) for each season and no more than three days a week in the summer.
  2. Start times - Find your "start times" function and adjust it so you run just one cycle in the early morning.
  3. Run time - Find your "run time" function and set it to a single run time of 30 to 90 minutes.

You also can access many irrigation clock manuals online.

Know your flow

Knowing the rate of flow of your irrigation system is essential to determining how many emitters can be placed on each valve.

Trade in your old clock

Replace your old irrigation clock with a smart controller. SNWA offers an instant rebate coupon.

Replace your battery

Power outages can cause your irrigation clock to revert to its factory settings, often watering your landscape far more than it needs or is permitted by mandatory watering restrictions. Replace your backup battery at least once a year — possibly at the same time you replace batteries in your home's smoke detectors — and avoid over watering.

Fast fixes for sprinkler problems

A quick, weekly check of your irrigation system can help sprinklers make the grade and ensure you don't run into bigger problems later.

After mowing, use the "manual" setting on your clock to turn on each sprinkler station for a couple minutes at a time. Check these items:

  • Misaligned heads: Adjust sprinkler heads that have shifted and are watering the street or driveway.
  • Obstructed heads: Taller grass around sprinkler heads will block your intended spray pattern. Make sure you have 3- or 4-inch pop-up sprinklers to fully clear taller grass.
  • Broken parts: Look for parts broken by your mower or foot traffic. Replace with identical parts for peak performance.
  • Head-to-head coverage: Each sprinkler's spray should just reach the next sprinkler head. Under-spray may result in dry spots, while over-spray wastes water.

Supervised testing of your irrigation system is allowed at any time of the day under mandatory watering restrictions.

Tree irrigation

Trees should be watered well enough to penetrate the soil to a depth of 18 to 24 inches. The type of tree and the season will determine a watering schedule.

Avoid these mistakes when dealing with drip irrigation for trees:

  • Setting your irrigation clock for your tree to run the same as spray irrigation
  • Mixing irrigation components
  • Not using filters or pressure regulators
  • Not property burying drip irrigation lines
  • Applying too much gravel mulch before establishing wetting patterns
  • Poor emitter placement which results in poor wetting patterns
  • Not maintaining the drip irrigation system