Parts of the Houston region are sinking, and in some areas, the ground has dropped more than a foot over the past two decades. Officials say reducing groundwater pumping can help slow the process, but the effects may not be immediate.
In the Katy area, one monitoring station recorded about 14 inches of subsidence between 2007 and 2025, according to the Harris-Galveston Subsidence District. The district’s data also show significant subsidence in parts of north and west Harris County.
Subsidence is the technical term for the gradual sinking of the ground. Across the Houston region, groundwater pumping is a major contributor. As water is removed from underground aquifers, the surrounding sediments can compact, causing the overlying land to subside.
The consequences can include increased flood risk and damage to roads and other infrastructure. It can also contribute to foundation damage.
But foundation cracks do not automatically mean subsidence is to blame. Soil conditions, drainage problems, tree roots and plumbing leaks can also cause foundations to move.
Medley D’Elia, who lives in west Harris County, invited us into her home to show us cracks she has noticed inside and outside the house.
D’Elia said one crack has grown since she moved in a few years ago. She is concerned about what that could mean for her home and her family’s finances.
“Your home is an investment, and I guess my biggest concern is, is the repair going to be costly, and is it a catastrophic issue that we have?” D’Elia said.
Bijay Aryal, a structural engineer with FIF Engineering, examined the home and identified separation in a brick joint that he said indicated foundation movement.
But that alone does not establish the cause.
Aryal said engineers can measure a home’s elevations and assess whether the foundation has shifted enough to warrant repairs. In some cases, he said, the best course is to monitor the home over time.
Much of the Houston area has clay-rich soil that expands when wet and shrinks as it dries. Those changes can put pressure on foundations. Trees, poor drainage, plumbing leaks and water collecting near a home’s foundation can also contribute to movement.
The Harris-Galveston Subsidence District has an interactive map showing subsidence rates across the region from 2021 to 2025. Residents can use it to see the measured sinking in their area, but even in areas that are subsiding, foundation issues may not necessarily be connected to subsidence.
A qualified professional, such as a structural engineer, can assess a home’s foundation, measure movement and consider other possible causes.
The Harris-Galveston Subsidence District was created by Texas lawmakers in 1975 to help prevent land subsidence. It regulates how much groundwater water providers can use and has phased in requirements to move communities toward alternative water supplies.
The district divides its jurisdiction into three regulatory areas, with different limits on groundwater use.
In Area 1, which includes coastal and southern parts of Harris and Galveston counties, water providers generally cannot use more than 10% groundwater.
In Area 2, which includes downtown Houston, the Texas Medical Center and parts of eastern Harris County, the limit is generally 20%.
Area 3 includes northern and western parts of Harris County, including communities around Katy and Fulshear. Providers there generally cannot use more than 40% groundwater. That limit is scheduled to decrease to 20% by 2035.
Mike Turco, the district’s general manager, said subsidence in these areas is directly related to the amount of groundwater being used.
Reducing groundwater use requires alternative sources of water and the infrastructure to deliver it. Regional water authorities develop those supplies and build pipelines and pump stations. Local water providers, including municipal utility districts, or MUDs, deliver water to homes and businesses.
One project intended to help reduce groundwater reliance is the Surface Water Supply Project, a joint effort involving the West Harris County Regional Water Authority and the North Fort Bend Water Authority.
The project brings surface water from Lake Houston to the Northeast Water Purification Plant in Houston for treatment. From there, transmission pipelines and pump stations move the water into the regional system.
Eric Hansen, board president of the West Harris County Regional Water Authority, said the project is designed to bring roughly 150 million gallons of water per day across the region.
Water is already moving through parts of the system, but not every community is receiving it.
Hansen said communities on the authority’s eastern side are being converted first because they are closer to the water source and less expensive to serve. The authority is expanding west and north as infrastructure is built.
Residents in Katy are not yet receiving surface water through this project, Hansen said, though communities are in the planning stages to receive it in the future.
The authority works with local water providers, including MUDs, but it does not directly deliver water to every home or set every customer’s final bill. Hansen encouraged residents to contact their local water provider to ask about plans and timelines for connecting to surface water.
The transition also affects water costs. Hansen said customers in areas that have not yet received surface water may already see a regional water authority charge on their bills. Those fees help fund the system, including infrastructure that will eventually serve communities farther from the water source.
Even after communities reduce their reliance on groundwater, subsidence may not stop immediately.
Turco said the timeline depends on the area’s geology and how much subsidence has already occurred.
He pointed to coastal areas where the district began regulating groundwater use in the late 1970s and early 1980s. Some monitoring stations did not show subsidence reaching zero until five to 10 years later.
“What we’ve seen down there is that the subsidence rates have flattened out,” Turco said. He said the district expects a similar change in western Harris County as communities continue shifting to alternative water supplies.
For homeowners, two things can be true at once: A foundation crack does not necessarily mean subsidence is responsible, but reducing groundwater pumping remains an important part of addressing subsidence across the region.
As the transition to surface water continues, residents can ask their local water provider or MUD when their community expects to connect. They can also consult the district’s subsidence map to understand the measured ground movement in their area.
