For the second year in a row, Arizona and Nevada will face cuts in the amount of water they can draw from the Colorado River as the West endures more drought, federal officials announced Tuesday.

Though the cuts will not result in any immediate new restrictions — like banning lawn watering or car washing — they signal that unpopular decisions about how to reduce consumption are on the horizon, including whether to prioritize growing cities or agricultural areas. Mexico will also face cuts.

But those reductions represent just a fraction of the potential pain to come for the 40 million Americans in seven states that rely on the river. Because the states failed to meet a federal deadline to figure out how to cut their water use by at least 15%, they could see even deeper cuts that the government has said are needed to prevent reservoirs from falling so low they cannot be pumped.

“The states collectively have not identified and adopted specific actions of sufficient magnitude that would stabilize the system,” Bureau of Reclamation Commissioner Camille Touton said.

Together, the missed deadline and the latest cuts put officials responsible for providing water to cities and farms under renewed pressure to plan for a hotter, drier future and a growing population.

Touton has said a 15% to 30% reduction is necessary to ensure that water deliveries and hydroelectric power production are not disrupted. She was noncommittal on Tuesday about whether she planned to impose those cuts unilaterally if the states cannot reach agreement.

She repeatedly declined to say how much time the states have to reach the deal she requested in June.

The inaction has stirred concerns throughout the region about the bureau’s willingness to act as states stubbornly cling to their water rights while acknowledging that a crisis looms.

“They have called the bureau’s bluff time and again,” Kyle Roerink, the executive director of the Great Basin Water Network, said of the Colorado River basin states. “Nothing has changed with today’s news — except for the fact that the Colorado River system keeps crashing.”

Stephen Lewis, governor of the Gila River Indian Community in central Arizona, said the tribe was “shocked and disappointed” by the lack of progress. The tribe, which is entitled to nearly one-fourth of Arizona’s Colorado River deliveries, no longer plans to save its unused water in Lake Mead, as it has in recent years, and instead plans to store it underground.

For years, cities and farms have diverted more water from the river than flows through it, depleting its reservoirs and raising questions about how it will be divided as water becomes more scarce.

After more than two decades of drought, Arizona, Nevada and Mexico were hit with mandatory cuts for the first time last year. Some of the region’s farmers have been paid to leave their fields fallow. Residents of growing cities have been subjected to conservation measures such as limits on grass lawns.

But those efforts thus far haven’t been enough. The water level at Lake Mead, the nation’s largest man-made reservoir, has plummeted so low that it’s currently less than a quarter full and inching dangerously close to a point where not enough water would flow to produce hydroelectric power at the Hoover Dam on the Nevada-Arizona border.

Officials in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming have been reluctant to propose more draconian water-rationing measures or limits on development.

The trade-offs are emerging most prominently in Arizona, which is among the nation’s fastest-growing states and has lower-priority water rights than water users to the west, in California.

Under Tuesday’s reductions, Arizona will lose an additional 80,000 acre-feet of water — 21% less than its total share but only 3% less than what it’s receiving this year.

An acre-foot is equivalent to an acre of land covered by 12 inches of water. An average household uses one-half to one acre-foot of water a year.

After putting last year’s burden on the agricultural industry, state officials said this year’s cuts would extend to tribes and growing cities that rely on the Colorado, including Scottsdale.

Rather than ration water, mandate conservation or limit development, the cities will likely shift reliance to other sources. Phoenix, for example, will rely more heavily on the in-state Salt and Verde rivers, while directing less of its supply to recharge its groundwater aquifers.

Arizona officials blasted neighboring states that haven’t proposed cuts even as Arizona implements its own.

Arizona and Nevada came up with a plan for cuts that would have been close to proportional to water use, but both California and the Bureau of Reclamation rejected that deal, state officials said.

“We need California to participate; we can’t do this alone with just Arizona and Nevada,” said Tom Buschatzke, director of the Arizona Department of Water Resources.

The effect of the cuts on farmers remains unclear, but many fear more cuts will further inflame tensions between cities and agriculture, which uses more than 70% of the basin’s water.

Paco Ollerton, a Phoenix-area cotton farmer, worries that deeper cuts could jeopardize his water next year. Arizona farmers already lost much of their Colorado River water during prior cuts, but they were compensated with water through deals with cities like Phoenix and Tucson.

This year, Ollerton grew only half of what he had grown previously. The cuts announced Tuesday could further squeeze those cities, raising questions about whether they will share with farmers next year.

“It kind of changes my thinking about how much longer I’m going to continue to farm,” Ollerton said.

Nevada also will lose water — about 8% of its supply — but most residents will not feel the effects because the state recycles the majority of its water used indoors and doesn’t use its full allocation. Last year, the state lost 7%.

Scorching temperatures and less melting snow in the spring have reduced the amount of water flowing from the Rocky Mountains, where the river originates before it snakes 1,450 miles (2,334 kilometers) southwest and into the Gulf of California.

Amid the changing climate, extraordinary steps are already being taken to keep water in Lake Powell, the other large Colorado River reservoir, which straddles the Arizona-Utah border.

After the lake fell low enough to threaten hydroelectric power production, federal officials said they would hold back some water to ensure the dam could still produce energy. That water would normally flow to Lake Mead.

Mexico will lose 7% of the water it receives each year from the river. Last year, it lost about 5%. The water is a lifeline for northern desert cities, including Tijuana, and for a large farming industry in the Mexicali Valley, just south of the border from California’s Imperial Valley.

Historically, Mexico has been sidelined in discussions over how to share the river, but in recent years, efforts by countries have been important to keeping more water in the system, experts say.

“People have come to realize this is a really important relationship to maintain,” said Jennifer Pitt, who directs the Colorado River program at the Audubon Society.