According to the state division of water resources, deciding not to water a lawn one time at an average single-family home could save 3,000 gallons of water.
The division recently resumed its weekly lawn watering guidelines. It recommends people hold off on watering as long as possible, ideally until there are a string of 70-degree days in a row.
Last week, the guidelines called for one watering per week in Summit and Wasatch counties, but this week, the division recommends not watering at all. Water Conservation Coordinator Shelby Ericksen said that’s due to low temperatures and precipitation in the forecast.
Ericksen said watering less could actually be better for the lawn.
“The guideline is to make sure you're not over-watering your grass. If you're applying more water than is needed, your grass roots are able to relax and they don't have to go down as deep to get water. And so that makes them less resilient to drought into the heat of the summer," Ericksen said. "So we're really recommending healthy lawns. We don't want stuff to die, but we don't want things to be over-watered.”
Ericksen said one watering is about 0.5 inches of water, and the timing varies between sprinkler systems. For spray sprinkler heads, that could take from five to 20 minutes, and for rotor heads that move around, it could be up to 40 minutes.
A key indicator for the guidelines is the evapotranspiration rate, or how quickly water from the ground evaporates into the air. Precipitation and cooler temperatures, both in the air and in the soil, slow that rate. And when the weather is hot, Eriksen recommends against cutting grass short.
“Keeping your grass longer definitely is better, it does shade your roots. So the water retention is better, you have less evaporation," Ericksen said. "So we recommend about three or four inches as the grass height.”
If there’s a big yellow spot in the middle of the lawn, Ericksen and her colleague Josh Zimmerman said it’s better to get out the hose to water just that area rather than running the entire sprinkler system.
Ericksen said educational entities like the Utah State University Extension can help determine whether an apparently dead spot is because of a lack of water or some other cause, like a nutrient deficit.
For more information, visit conservewater.utah.gov.
