The Great Salt Lake is shrinking because nearly half the water that should flow into it gets consumed before it arrives. The three rivers feeding the lake, the Bear, Weber, and Jordan, have been so heavily diverted for farming and city use that between 2020 and 2023, the lake received less than a third of its natural streamflow. Climate change compounds the problem by increasing evaporation and reducing snowpack. Together, these forces pushed the lake’s south arm to its lowest recorded elevation in 2022, and it remains dangerously low today.
Water Diversion Is the Biggest Factor
The Great Salt Lake has no outlet. It depends entirely on three rivers, the Bear, Weber, and Jordan, plus direct precipitation and groundwater to maintain its volume. An estimated 45% of the annual surface water flowing from those rivers is consumed by agriculture, cities, and industry before it ever reaches the lake. Between 70% and 82% of Utah’s total diverted water goes to agriculture, primarily irrigation.
The numbers are striking when you look at each river individually. On the Bear River, agriculture accounts for about 93% of all water withdrawn. On the Weber River, farming’s share dropped from 83% in 1985 to 62% in 2015 as urban demand grew. On the Jordan River, agriculture’s portion fell from 71% to 55% over the same period, again because municipal use expanded rather than because total withdrawals decreased. The lake doesn’t benefit either way: the water is still gone.
Residential water use adds a surprising layer. Roughly 600,000 acre-feet of Utah’s residential water, about 192 billion gallons per year, is diverted from rivers that would otherwise feed the lake. Much of that goes to outdoor landscaping. As recently as 2023, there were proposals to revive the Bear River Development Project from the 1990s, which would divert an additional 30% of the Bear River’s average flow, largely to water lawns in northern Utah’s growing suburbs.
Climate Change Makes the Problem Worse
Water diversion alone didn’t push the lake to its record low. A 2024 study published in Geophysical Research Letters found that unusually low streamflow was the largest driver of the lake’s record low volume in 2022, responsible for roughly three times as much water loss as increased evaporation. But the lake would not have reached that historic low without the added push from rising temperatures.
Warming affects the lake in two ways. First, hotter air increases evaporation directly from the lake surface. Second, and more subtly, warming reduces the snowpack that feeds the rivers in spring. Satellite data show that rising temperatures in the Great Salt Lake basin have caused less precipitation to fall as snow, lower snow depth, and earlier snowmelt. The watershed’s snowpack has been declining faster than most other Western U.S. watersheds, and climate models project that trend will continue. Less snowpack means less spring runoff, which means less water reaching the lake even in years without extreme drought.
These two forces, diversion and climate, interact in ways that are hard to untangle. Warmer temperatures don’t just evaporate the lake itself; they also increase evaporation from soil and vegetation across the entire watershed, reducing how much water makes it into the rivers in the first place.
Where the Lake Stands Now
The lake’s south arm ended the 2025 water year at 4,191.1 feet, the third-lowest recorded elevation since monitoring began in 1903. The all-time low came in 2022. While two consecutive wetter years have provided modest relief, the lake remains far below the levels needed to sustain its ecosystem. Research suggests that increased streamflow can lead to rapid volume recovery, but continued warming will keep pushing in the opposite direction.
Rising Salinity Threatens the Ecosystem
As the lake shrinks, its salinity climbs. The Great Salt Lake’s salinity ranges from about 60 to 250 parts per thousand depending on location and water level (for comparison, the ocean sits around 35 parts per thousand). Brine shrimp, the foundation of the lake’s food web, can tolerate extreme salt levels, but lab experiments show their populations begin to collapse once salinity exceeds 120 to 150 parts per thousand. Above that range, reproduction drops and survival plummets.
This isn’t just an ecological concern. The lake’s brine shrimp are harvested commercially and sold as fish food for aquaculture worldwide. Millions of migratory birds, including eared grebes, Wilson’s phalaropes, and American avocets, depend on brine shrimp and brine flies as fuel during their long-distance migrations. If salinity stays too high for too long, the biological engine of the lake shuts down.
Exposed Lakebed Creates Health Risks
Every foot the lake drops exposes more lakebed to the wind. That dry sediment contains arsenic from both natural geological sources and decades of human activity, along with lead, copper, thallium, nickel, and other heavy metals deposited by mining, coal burning, and agricultural runoff. When wind kicks up dust from the exposed lakebed, those particles can travel directly into Salt Lake City and surrounding communities.
The health concern is straightforward: roughly 2.5 million people live along the Wasatch Front, downwind of the lake. Breathing fine particulate matter laced with arsenic and heavy metals raises the risk of respiratory illness, and the more lakebed that’s exposed, the larger the dust source becomes. Researchers are actively measuring metal concentrations in lake dust to better understand the scale of the threat, but the basic risk is already clear. A shrinking lake is a public health issue, not just an environmental one.
What Utah Is Doing About It
Utah’s legislature has started passing water conservation laws aimed specifically at the Great Salt Lake Basin, though critics argue the measures don’t yet match the scale of the crisis. In 2024, a new law restricted overhead spray irrigation on government, school, and highway properties in the basin, limiting sprinklers primarily to active recreation areas like sports fields and playgrounds. Another bill gave the State Engineer authority to require standardized water data reporting in the basin and clarified eligibility for water conservation grants.
A separate law directed the state to study conditions at Utah Lake, a freshwater lake that drains into the Jordan River and ultimately feeds the Great Salt Lake, specifically examining whether Utah Lake’s management is limiting water delivery downstream. These are incremental steps. The fundamental challenge remains that existing water rights allow far more water to be diverted from the lake’s tributaries than the lake can afford to lose, and changing those rights is politically difficult in a state where agriculture and suburban growth both depend on cheap, abundant water.