The Los Angeles Department of Water and Power’s $18 million annual turf rebate program is a “gimmick” and has saved a negligible amount of water compared with other measures, Los Angeles Controller Ron Galperin stated in an audit released Friday.

While the program “spurred a heightened awareness” about the drought, ripping out lawns wasn’t the most efficient way to use taxpayer money, Galperin said.

His analysis comes after water agencies throughout Southern California paid hundreds of millions of dollars for residents and businesses to plant drought-tolerant landscaping. As the state weathers its fourth year of drought, officials have reflected on which conservation measures are worth continuing.

“Turf rebates are, quite frankly, not the most cost-effective way to encourage savings,” Galperin said at a news conference Friday. “That doesn’t mean they were useless. They had value as a gimmick — that is, a device intended to attract attention and publicity.”

The DWP paid customers up to $1.75 per square foot of lawn removed in 2014, the peak of the program, in addition to $2 from the Metropolitan Water District of Southern California, the region’s wholesale water agency.

Since 2009, the DWP has spent more than $42 million on commercial and residential turf rebates, according to figures provided by the agency.

Galperin contrasted the investment with other water conservation rebates, such as those for high-efficiency clothes washers and high-efficiency toilets.

Those programs are expected to save more than 1,700 gallons of water for every ratepayer dollar invested, his audit found, compared to approximately 350 gallons for turf removal. Savings are accumulated over the lifetime of the investment; turf, for instance, assumes a 10-year lifespan.

In fiscal year 2015 alone, the DWP spent $17.8 million to replace turf, Galperin’s audit found, compared to $14.9 million spent on appliances and other conservation rebates.

The appliance programs, though, have reached “market saturation,” the department said in a statement — in other words, the city has provided rebates to all customers it expects would accept them.

“So while we continue to offer rebates for indoor water savings,” Marty Adams, DWP senior assistant general manager, wrote, “LADWP’s turf replacement program has helped us target the largest remaining opportunity for broad-based water savings — outdoor water use.”

It’s a potentially large target: About 40 to 60 percent of a typical L.A. home’s water is used outdoors, one DWP official said. Drought-tolerant landscaping in Southern California saves roughly 45 gallons per square foot per year, according to a report by the California Urban Water Conservation Council. That report also questioned turf rebates’ cost-effectiveness, but found the incentives could affect “social norms.”

“It’s a visual reminder to people,” said Penny Falcon, manager of water conservation at the DWP. “It’s a social change we’re trying to make — getting people to live more sustainably.”

While Galperin stopped short of calling for an end to the turf replacement program, he recommended other measures. Customers should be rewarded for actual water savings, he said, and the DWP could provide incentives for “smart meters” that would enable people to closely track their water use.

Galperin also said he believes the DWP should release the names and addresses of turf rebate recipients. The department has fought disclosure in an ongoing court case, arguing for customers’ privacy rights.

Also, he recommended “submeters” for multifamily residential buildings, another way to monitor conservation. Today, many of the city’s apartment buildings, especially older ones, operate with a central water meter.

Stephanie Pincetl, director of the California Center for Sustainable Communities at UCLA, said metering is actually one of the problems with turf rebates. Most homes have one meter for the entire property, instead of an outdoor and indoor meter.

“It’s hard to know how to manage (rebate programs) if you don’t know how much is used,” she said.

Two of Galperin’s other recommendations — investment in water infrastructure and restructuring rates to encourage conservation — are already part of a DWP rate proposal working its way through the city bureaucracy.

The city is on track to meet conservation targets set by Mayor Eric Garcetti and Gov. Jerry Brown, according to the department. On a per-capita basis, Angelenos use 107 gallons per person per day — an 18 percent reduction from fiscal year 2014.

How much of that is attributed to turf rebates is difficult to say, although department officials see a correlation. The DWP doesn’t measure savings for each particular consumer who takes a turf rebate.

“In the past, it’s been fine to ask ratepayers to pay for broad programs,” said UCLA’s Pincetl, but now utilities “need different kinds of analytics — what has worked, and where.”