Automatic sprinkler systems are convenient, but they often waste 40-50% of the water used. If you have an automatic, in-ground sprinkler system, annual maintenance, fine-tuning and proper schedules are the best ways to save money and improve the health of your landscape.

• Water Better with the Weather



• Choose Equipment to Save Water



• Save Money by Changing How You Water



• Maintain Your System for Best Performance

The key to efficient irrigation is to adjust watering schedules frequently during the season. If you set your automatic controller once and let it run all season, you’re wasting a lot of water that could be hurting your plants along with your wallet. Most modern controllers allow you to easily adjust your watering schedule based on the weather—see below for more information. Or you can install a “smart” controller that adjusts the schedule for you.

Watering schedules should be based on the Evapotranspiration (ET) rate for the Seattle area. Local ET rates are calculated with weather station data, which includes temperature, humidity, wind, and day length (solar radiation).

ET indicates how much water needs to be applied to plants to stay healthy. Since plants use more water when the days are longest, watering schedules that gradually increase into July and gradually decrease into September can increase plant health.

To calculate how much water your landscape needs and to change your watering schedule throughout the season with ET information, try these handy tools on the Irrigation Water Management Society website

• Use the current Watering Index for the Seattle area to adjust your water schedule with the "Percent Adjust" or "Water Budget" feature found on most modern controllers. The Index is a percentage of the peak watering period. "Peak" refers to the time of year when days are the longest and the weather is the hottest, typically between June and July. In July, the Watering Index usually reads around 100%, sometimes over 100%, which means that watering schedules should be set to water the maximum that plants need. In September, even though it is still hot and dry, it is common for the index to read around 50% because the days are shorter and plants do not need as much water. This means that watering schedules in September should be about half as much as they are in July.
• Estimate your landscape's watering requirements with the Water Budget Calculator, using historic ET data and the square footage of your landscape.
• Create a customized watering schedule for your landscape plantings and watering system by using Sprinkler Calculators.

• Install a “smart” sprinkler controller that automatically adjusts the watering schedule to reflect actual environmental conditions. These easy-to-use controllers can reduce sprinkler water use by up to 30% while actually improving plant health. The Saving Water Partnership offers rebates of up to $450 on any qualifying “smart” controller. For more information about “smart” controllers, visit the Irrigation Association.
• Get rebates for improving the water efficiency or your irrigation system.
• Match heads in each zone to apply equal amounts of water. Spray heads and rotors have different application rates, so with unmatched heads some areas get more water than others.
• Use check valves to eliminate low-head drainage. If heads leak after the zone has completed its cycle, the system is wasting water. Heads with built in check-valves keep the water from draining from the pipe.
• Ask your irrigation contractor to make recommendations for upgrades that will save you water and money. For information on certified irrigation professionals in the Seattle metropolitan area, see Choosing a Contractor (pdf).

• Adjust controller runtimes regularly during the season by utilizing the Watering Index.
• Set your controller to irrigate at night or before 10:00 AM to reduce evaporation.
• Watch for water running off of irrigated areas. If run-off occurs soon after watering begins, use the "Cycle & Soak" feature on your controller or set multiple start times for each zone to allow the water to soak in after each “cycle.” .
• Turn down the flow control at the valve or use pressure-regulating heads if you have misting or overspray. If all zones have excessive pressure, a pressure-regulating valve can be installed at the point of connection.
• Convert beds to soaker hoses, micro-sprinklers or drip systems.
• Reduce watering of established shrubs. Most trees, once established, do not need supplemental water.

• Have your sprinkler system tuned-up by a certified irrigation professional (pdf) at the start of every watering season. Observe your sprinkler system running at least once a month to look for broken heads, leaks, plants blocking heads, and other water wasting problems.
• Look for suspicious spots in your landscape that are much greener or consistently wet and muddy. Underground leaks can be difficult to identify and may need to be located by a specialist.
• Fix conditions where water runs off or is spraying the driveway, sidewalk, or other areas that don’t need to be watered.
• Cap sprinkler heads that are no longer needed.

By using the latest in advanced irrigation control technology, adjusting your schedule regularly and properly maintaining your sprinkler system, you will help ensure the health of your landscape while conserving water and saving money.