Turf war: Overwatering our lawns is sucking up our water supply

Getting her first $300 water bill was all it took for Hollie Jones to yank the plug on her automatic sprinkler system.

"It blew me away," said Jones, who was new to yard upkeep when she moved into her Brooklyn Park home four years ago. "I was wasting tons of water and turning my yard into a jungle."

For Jones, the decision to start running her sprinkler system on an as-needed basis made financial sense, but scientists say this kind of tweak in lawn care could yield crucial benefits in water conservation. During the summer months, water use in the metro area surges, in some places tripling compared with the amount of water pulled from rivers and aquifers in the winter. And that seasonal gap is widening.

Researchers from the Metropolitan Council and the University of Minnesota Extension suspect bad watering habits are largely to blame. So they've been conducting lawn water use surveys and visiting neighborhoods over the past few months, studying sprinkler systems and irrigation trends across the region.

The coming decades, they say, may only exacerbate strains on the water supply, with state demographers predicting the metro area will swell by more than 400,000 people in the next 25 years. At current water use rates, that means aquifer levels in some areas could drop more than 40 feet by 2040, according to Met Council groundwater model estimates.

"We are not in the emergency room, but we are in urgent care," said Ali Elhassan, water supply planning manager for the Met Council.

The biggest concern, he said, is not with water shortages, but with the impact that these declining levels may have on the state's beloved resources — including lakes, wetlands and trout streams.

Overwatering habits

Researchers believe reducing the winter-summer ratio to its 1990s levels could slash total water use in the metro area by 15 percent. That's where lawn watering — and overwatering — habits come in. While efficient appliances have reduced indoor water use in many cities, outdoor use in the summer, driven by lawn irrigation, continues to climb.

"Most people water way more than they need to," said Eric Watkins, University of Minnesota associate professor and turf-grass expert. "You really need to water very little in Minnesota."

The goal of the $122,000 study, paid for by the Clean Water Fund through a Met Council grant, is to compare common irrigation systems with more efficient alternatives. The research team plans to set up and analyze various systems at the university's St. Paul campus next spring.

In May, U Extension researchers posted an online survey, asking residents about their home type, lawn size and watering practices. Respondents like Jones could also sign up for a free, in-person assessment of their irrigation system. From 800 survey responses so far, the team has done 40 lawn audits, with 20 more to go.

During these visits, they've found that roughly half of homeowners hydrate their lawns every other day — often much more than necessary.

"You can still have a green lawn and not have to put much water on it," said Sam Bauer, a turf-grass science educator at U Extension.

Bauer often suggests residents consider switching to grass species like fine fescue, which guzzle much less water than the more popular Kentucky bluegrass species.

And regardless of grass type, Bauer gives this tip: "Water your lawn deeply and infrequently," he said. "Wait as long as you can — it pushes your root growth deeper into the soil."

Curbing summer surges

Many cities around the metro have set up watering restrictions to lessen the summer spike.

In Woodbury, where residents draw from as many as 14 wells in the summer months — compared with just a handful used in the winter — the city now enforces tiered water rates, uses time-based watering guidelines and has even given away 100 smart sprinkler controllers. The controllers allow residents to keep tabs on their watering systems from their cellphones and sync to local weather stations so sprinklers don't pop up when it rains.

Dan Philippi uses a controller as he follows the scrupulous fertilizing, weeding, watering and mowing regimen that keeps his Woodbury lawn pristine.

"I like to take care of the things I have," said Philippi, who participated in the study.

But he also tries to do his part to conserve water. Before, that meant dashing out in the middle of the night to shut off the sprinklers if it rained. With his smart control system now in place, Philippi feels he can hold onto his Kentucky bluegrass and water as needed.

"Water is without a doubt one of the best resources this state has," Philippi said. "We're very fortunate, and we don't want to mismanage it."

But when it comes to lawn care, changing habits can be tricky, researchers say. There's plenty of pressure to keep up with the neighboring turf.

"The social norms of your neighborhood and knowledge matter," said Kristen Nelson, a U professor who has studied lawn care behaviors for 10 years.

The trick is getting the information to chatty neighbors who will then pass the knowledge along, she said. And with some water well levels showing consistent decline, hydrologists say the time to spread the word about inefficient use is now.

"There are likely going to be some [water supply] concerns and issues in certain areas," said Jason Moeckel, section manager for the Minnesota Department of Natural Resources. "But we've got time and an opportunity to work to address it."

Hannah Covington • 612-673-4751