In drought-stricken California, the state and dozens of water agencies embarked upon a unique social experiment: try to break the love affair with the lawn by paying residents to rip out their turf and replace it with less thirsty landscaping.

San Francisco-based environment reporter Ellen Knickmeyer, who has been covering the state’s historic five-year drought, decided to dig into the water-saving strategy and determine whether it was worth the cost.

There was no central repository of information about the money spent. Starting in 2014, the amount put into such programs shot up from millions of dollars to hundreds of millions. Knickmeyer contacted state agencies and water districts to obtain data on how much they spent on the rebate programs and how many residents took part.

Knickmeyer, for example, obtained spreadsheets of all rebates given by the state’s largest water supplier, serving 17 million people in Southern California. She searched the data for patterns, using skills sharpened at a data-journalism workshop in New York in August.

Residents received more than $350 million in rebates for tearing out water-sucking lawns, and spending by local and regional water agencies dwarfed the state’s $25 million program.

She learned that residents received more than $350 million in rebates for tearing out water-sucking lawns, and that spending by local and regional water agencies dwarfed the state’s $25 million program.

Knickmeyer discovered, too, that they were using technology, including satellite images and infrared aerial photos, to figure out not only how much lawn was removed but also whether the program succeeded in shifting tastes from lush green turf to more drought-resistant plantings.

Now, some water-district managers are concerned, fearing that the benefits won’t measure up to the costs of the program at this early date.

Her comprehensive look at the experiment in social engineering resonated with customers. Major California newspapers featured the story. Among them were the websites of the Los Angeles Times, San Francisco Chronicle, Sacramento Bee, Orange County Register and the Mercury News in San Jose.

The piece, accompanied by a mobile-friendly Things to Know, was promoted on social media with photos by Eric Risberg and video shot by Knickmeyer. She was interviewed by Southern California’s NPR station about her story.

For digging out a government accountability story that shed light on the centerpiece of California’s drought spending, Knickmeyer wins this week’s $300 Best of the States prize.