In parts of the San Joaquin Valley, sinking land has become such a serious problem, it\u2019s beginning to depress home prices, new research shows. <\/p>\n
Homes in large portions of California\u2019s Central Valley have been sinking, as have roads, bridges, canals and levees, as too much water is drawn out of underground aquifers.<\/p>\n
Now researchers at UC Riverside have found<\/a> that home prices are 2.4% to 5.4% lower than they would be if the land were stable, translating to losses of $6,689 to $16,165 per home. The study looks at sales between 2015 and 2021.<\/p>\n Mehdi Nemati, a UC Riverside assistant professor of environmental economics and policy who led the study, said his team knew that sinking land was already affecting homeowners across the Central Valley, with cracking foundations, wells going dry, higher insurance premiums and increased stress. But he said they were startled by their results. <\/p>\n \u201cWe were surprised because land subsidence is not like flooding or wildfires,\u201d Nemati said, describing those climate-fueled disasters as much more visual and sudden. \u201cLand subsidence is a very slow problem.\u201d<\/p>\n The economists found that land subsidence has lowered the value of homes across eight counties in the San Joaquin Valley by $1.87 billion over the six-year period.<\/p>\n \u201cWhat this study does is tells us that it\u2019s not just ground sinking, it\u2019s a billion-dollar problem tied to decades of groundwater overuse,\u201d Nemati said.<\/p>\n The study, published in the journal Land Economics<\/a>, analyzed home sales and \u201cvertical land surface displacement\u201d across the San Joaquin Valley. <\/p>\n Although it was clear there was a strong correlation between areas with higher rates of subsidence and more dramatic drops in home values, he said his team spent more than a year to establish causation. They did that by taking pairs of similar homes, each of which sold twice during the six-year period, one in an area with subsidence and one not.<\/p>\n \u201cIn general, home values in California \u2014 as you know \u2014 are going up,\u201d Nemati said. \u201cBut homes that were in subsidence areas, they experienced a much smaller increase.\u201d<\/p>\n Agricultural wells have been drawing heavily on groundwater for decades, lowering aquifer levels. That has caused underground clay layers to compact. <\/p>\n The phenomenon has been altering the San Joaquin Valley\u2019s landscape since the early 1900s. But during the last decade, the ground in some areas has sunk faster. In a recent study<\/a>, Stanford University researchers found the problem has been worsening.<\/p>\n Parts of Tulare and Kings counties are subsiding up to a foot or more a year. <\/p>\n The problem has deepened as climate change has unleashed longer and more intense droughts<\/a>.<\/p>\n Under California\u2019s groundwater law, local agencies must work toward plans<\/a> to limit pumping and address overdraft by 2040. One of its aims is to address land subsidence. <\/p>\n