Report: Smart Lawn Watering Could Save Big

Even Texans with the greenest of lawns water them too much, many landscape experts say. And if everyone would turn on the sprinklers only twice a week — still probably more than necessary — the water savings would be significant, according to a report from the Sierra Club released Tuesday.

In the Dallas and Houston regions, about 52 billion gallons of water per year could be saved just by cutting back lawn watering, the report says. That's enough to supply almost half a million Austin-area homes for a year. And the numbers include lawns with St. Augustine grass, among the thirstiest of choices for a green lawn. 

“Even if you have [St. Augustine] and you want to maintain it, you don’t need to water as much as you have been doing,” said Ken Kramer, water conservation chairman of the Sierra Club’s Lone Star Chapter.

The projections are based on the known effects of twice-a-week lawn-watering restrictions in various Texas cities. Only a handful of cities, including Dallas, Fort Worth and Irving, have such limits in place year-round, regardless of whether there’s a drought.

Environmental groups say these findings show that addressing Texas’ water problems doesn’t always require building controversial new reservoirs or expensive infrastructure. While the Houston and Dallas areas are projected to double in population by 2060, the savings of twice-a-week-watering would double as well, to 95 billion gallons of water annually, the report says. That's equivalent to more than half of what the proposed Marvin Nichols reservoir would provide for North Texas, if the controversial $3.4 billion project ever gets built.

But the data has its shortcomings, other experts say. The Sierra Club found that Dallas’ twice-a-week lawn-watering ordinance reduced its water use by 8 percent, but Jody Puckett, director of the city’s water utility, said other cities may not see similar savings. Some cities have more industrial water use than others, for instance, so limiting outdoor watering might not produce the same results.

Puckett also pointed out that many cities in the Dallas area have lawn-watering restrictions because of drought restrictions right now. That means they’re already realizing water savings today that the Sierra Club’s report may not have taken into account, and there’s also no way of knowing how many drought-conscious residents are already conserving extra water.

Robert Mace, a top official at the state’s water board, added, “We’re growing too fast to meet our needs solely through water conservation.” Cutting lawn watering even by half might delay the need for new supplies and projects to 2020, he said, but they’ll probably still be needed by 2030.

Still, a 2012 study from the Texas Water Development Board found a potential for huge water savings even on traditional lawns. “Irrigation applied to most Texas lawns is actually double what is necessary for a healthful appearance," the agency wrote.

John Taylor, who runs a landscaping business in the Houston area, thinks the savings could be even greater. “The average acre of landscape within the state of Texas is over-watered by more than 200 percent,” and that can even damage the lawns’ soil, Taylor said.

In most of the homes Taylor’s business looks at, half of the water released by the sprinklers never makes it to the part of the grass’ roots that needs it. And with automatic irrigation systems, which are becoming more common in new Texas homes, the sprinklers turn on even when it’s raining.

“You run the sprinkler system too often, you run the zones too long, you’ve got broken sprinkler heads that you don’t know about” — all of those are common reasons for over-watering, said Ron Kaiser, a professor of water policy at Texas A&M University.

By studying what happened when 5,500 of the wealthiest homes in College Station got free irrigation checkups and educational tips about lawn care, Kaiser found water savings of 200 million gallons over a three-year period. Hundreds of homes collectively use that much water every year.

Beyond smarter lawn watering, experts and conservation groups see bigger savings in landscapes. Replacing grass with native, drought-resistant plants can save huge amounts of water: Just 80 San Antonio homes that limited the amount of turf on their lawn and only used approved plants saved more than 2.2 million gallons, according to that city’s water utility.

But the hurdles are still large. Even in San Antonio, considered one of the most conservation-minded cities in America, as much as 40 percent of the city’s water use during summer is estimated to go on lawns. That amounts to 20 percent over the entire year, the San Antonio Water System estimates.

So far, the city still allows once-a-week watering, drawing the ire of critics who say it’s ignoring a dwindling Edwards Aquifer. And avoiding more severe restrictions has been cited by many as a reason for the city moving forward with a controversial, multibillion-dollar new water project last fall.

“You can’t keep your yard, your shrubs alive under those restrictions," City Councilman Joe Krier said in an interview last year. "That is the same thing as not having any water. We’ve got to have a system and a supply of water that says, you can keep your single largest investment, your home, looking good in good times and in bad."

Disclosure: Texas A&M University and the San Antonio Water System are corporate sponsors of The Texas Tribune. The Sierra Club was a corporate sponsor in 2011. A complete list of Tribune donors and sponsors can be viewed here.