California is not sinking into the ocean, and it never will. The tectonic plates beneath the state move sideways, not downward, so there is no geological mechanism that could drag the state underwater. But parts of California are genuinely sinking, some at alarming rates, and when combined with rising seas, the practical effects can look a lot like what people imagine when they picture the state disappearing beneath the waves.
Why California Can’t Fall Into the Ocean
The idea usually traces back to the San Andreas Fault, the 800-mile crack running through western California where two massive tectonic plates meet. The Pacific Plate sits on the west side, and the North American Plate sits on the east. These plates don’t pull apart or push one under the other at this boundary. They slide horizontally past each other in what geologists call a right-lateral strike-slip fault. If you stood on one side of the fault and watched the other side, it would appear to drift to the right.
GPS surveys confirm the Pacific Plate is creeping northwestward at up to 2 inches per year relative to the North American Plate. That means the sliver of California west of the fault (including Los Angeles) is slowly heading toward Alaska, not toward the ocean floor. In roughly 15 million years, Los Angeles and San Francisco will be neighbors. Neither city will be underwater because of plate movement.
The Places That Are Actually Sinking
While the tectonic story is reassuring, significant portions of California are physically dropping in elevation, just not for the reasons most people assume. The biggest culprit is groundwater pumping. California’s Central Valley, one of the most productive agricultural regions on Earth, has been sinking for decades as farmers draw water from underground aquifers faster than rain and snowmelt can replenish them. When the water is removed, the clay layers in the soil compact under their own weight and the land surface drops. NASA satellite measurements have identified trouble spots in the valley still sinking at rates as high as 2 feet per year. That kind of subsidence buckles canals, cracks roads, and permanently reduces the aquifer’s ability to store water in the future.
The state passed the Sustainable Groundwater Management Act in 2014 to address this, requiring local agencies to bring their basins into balance by the 2040s. Progress has been mixed. Active subsidence continues across the Sacramento River, San Joaquin River, and Tulare Lake regions, though state officials say local agencies have made meaningful investments in flexible water strategies since 2020.
Coastal Cities Sinking From Below
The coast has its own sinking problem, separate from agriculture. A 2024 study published in Science Advances used satellite radar measurements to track vertical land motion along California’s shoreline and found that several major urban areas are subsiding faster than previously estimated. La Jolla, near San Diego, is dropping at about 1.5 millimeters per year. Point Reyes, north of San Francisco, is sinking at roughly 2.8 millimeters per year. Parts of Los Angeles and San Diego face subsidence driven by decades of oil and groundwater extraction beneath the surface.
These numbers sound tiny in isolation. But they compound over decades, and they stack on top of rising sea levels. The study found that regional sea level rise projections substantially understate the actual risk in parts of San Francisco and Los Angeles, with some areas facing more than double the expected rise by 2050 once local land sinking is factored in. In certain spots around Los Angeles and San Diego, this land motion alone adds up to 0.4 meters (about 16 inches) of uncertainty to 2050 projections.
San Francisco’s Vulnerable Shoreline
San Francisco has a specific version of this problem. Large sections of the city’s waterfront, including neighborhoods in San Francisco, Oakland, and Alameda Island, were built on artificial landfill placed decades ago over what was once submerged bay floor. This fill material settles and compacts over time, gradually lowering the ground surface. It also creates serious earthquake risk: during the 1989 Loma Prieta earthquake, the Marina District experienced liquefaction, where saturated fill lost its structural integrity and buildings sank into the softened ground. These same low-lying fill areas are the most exposed to future flooding as sea levels climb.
What Rising Seas Mean in Practice
California’s Ocean Protection Council projects a statewide average of 0.8 feet of sea level rise by 2050, with the possibility of nearly a foot in some areas. Looking further out, seas could rise up to 12 feet by 2150. The council has warned that coastal flooding frequency is already increasing and will accelerate noticeably in the next decade.
The U.S. Geological Survey has modeled what this means in concrete terms. With just 10 inches of sea level rise (expected within 30 years), every high tide could flood areas where 37,000 people live and 13,000 people work, putting $8 billion in property at risk of damage. Add an extreme storm on top of that modest rise and the numbers jump dramatically: more than 150,000 residents flooded, 86,000 employees affected, and $32 billion in real estate exposed. These aren’t distant hypotheticals. They fall within the lifetime of a mortgage signed today.
The infrastructure at risk includes energy facilities, industrial contamination sites, public health buildings, and subsidized housing. An analysis of critical assets found that as many as 392 could face disruptive flooding by mid-century or end of century, with contamination sites posing a particular concern because floodwaters can spread toxic materials across wide areas.
Sliding Sideways, Sinking Slowly
So California isn’t falling into the Pacific, and it won’t. The geology simply doesn’t work that way. But the state faces a real and measurable sinking problem from two directions at once: agricultural regions losing elevation to groundwater depletion, and coastal cities quietly subsiding while the ocean rises to meet them. Neither process is dramatic enough to notice day to day. Both are serious enough to reshape where and how millions of Californians live within the next few decades.