California’s Central Valley has experienced record land subsidence in recent years, driven by droughts and groundwater extraction. Between 2006 and 2022, the San Joaquin Valley sank at an average rate of nearly one inch per year, according to Stanford University research.
A new study by UC Riverside sheds light on how this sinking has impacted property values in the region. The researchers used satellite radar data to measure ground-level changes across eight counties in the Valley. They then compared that data to nearly 200,000 home sales recorded between 2015 and 2021.
They concluded that land subsidence caused losses of $6,689 to $16,165 per home in the most affected areas. That represents between 2.4% to 5.8% of home values. Total losses across the region were estimated at approximately $1.87 billion.
"Our research shows that subsidence is not just an agricultural or environmental issue,” said study co-author Ariel Dinar, professor emeritus of environmental economics and policy at UC Riverside. “It is a serious economic issue that affects families and communities.”
California has long been aware of the dangers of over-pumping. In 2014, the Sustainable Groundwater Management Act (SGMA) was passed to prevent groundwater depletion. SGMA requires local agencies to develop and implement groundwater sustainability plans. But progress has been slow and uneven — and the policy itself is controversial with local agencies and farmers.
Last year, the State Water Resources Control Board placed the Tulare Lake Subbasin under probation for failure to comply with SGMA. The Kings County Farm Bureau sued the state, calling it “an act of State overreach.” The City of Lemoore filed an amicus brief in the case, supporting the Farm Bureau’s legal challenge. A judge ultimately granted a preliminary injunction, halting the state’s sanctions. California has since appealed that ruling.