California’s water problem won’t be solved by shorter showers or browner lawns.

In Gov. Jerry Brown’s executive order setting California’s mandatory water reductions in cities and towns, he called for 25 percent reductions in use that would save 1.5 million acre-feet of water over the next nine months.

By comparison, the city of Los Angeles uses 587,000 acre-feet in a year. In other words, L.A. would need to go completely dry for three years to cover Brown’s goals on its own.

California’s urban areas are responsible for only 10 percent of the state’s water use. Even as the cities have grown, urban per-capita consumption has declined, from 232 gallons per day in 1990 to 178 gallons per day in 2010. As a result, the cities’ total water use has been relatively stable.

Instead, the thirstiest sector of the state is the agricultural industry, which makes up 40 percent of water usage. If you set aside the 50 percent of California’s water that’s reserved for environmental use (maintaining wetlands, rivers, and other parts of the state’s ecosystem), agriculture uses 80 percent of the remaining water dedicated directly or indirectly for human uses.

In the week before Brown’s restrictions were finalized, an op-ed piece in the Los Angeles Times called on Brown to deny agriculture an exemption from any new cuts. In the article, Ted Rall argued that restrictions on farms would keep ordinary citizens from feeling unfairly singled out and asked: “Isn’t it easier and cheaper to regulate the water consumption habits of a few thousand huge farms than of millions of individual households?” Adam Scow, the California Director of the Food and Water Watch, told the San Diego Free Press that Brown’s policies gave agricultural interests a “free pass.”

Sure enough, Brown’s executive order doesn’t touch the farms, except to step up data collection to find companies and farmers that are breaking existing rules. Instead, the 1.5 million acre-feet reduction will come from towns and cities meeting this new reduction goal, however they can. The state is providing a little help by instituting a temporary rebate program to encourage consumers to trade in their old appliances for more efficient models.

These programs are all focused on chasing modest gains, perhaps because it’s easier (and less costly to the economy) for residents to make changes in the near term than it is for industry.

Farmers who have already planted crops for the year can only alter their irrigation plans so much without putting their harvest at risk. Almond orchards, one of California’s most water-costly industries (3,375,000 acre-feet per year, more than double what the cities are being asked to cut), may be particularly resistant to reductions. Farmers who invested in trees may have expected to cover their start-up costs after years of harvests and have more to lose in switching crops.

Addressing California’s water crisis will likely require long term re-planning from industry, not just short term scrimping from its residents.