The State of Our Aquifers: south Montgomery County still shows the deepest long-term drops
USGS hydrologist Jason Ramage told a Woodlands Green audience on September 24 that long-term groundwater declines of more than 360 feet are concentrated in south-central Montgomery County, while converted parts of Harris and Galveston counties have recovered.
The Woodlands Green presented “The State of Our Aquifers” on Thursday, September 24, 2026, with Jason Ramage of the U.S. Geological Survey. The free lecture, at the Houston Advanced Research Center at 8801 Gosling Road and on Zoom, covered the newest regional water-level maps for the Chicot, Evangeline, and Jasper aquifers, and the compaction records USGS extensometers have kept across the Houston area. The full talk is on The Woodlands GREEN YouTube channel.
What the 2026 maps show
Ramage said the USGS measures a regional well network each winter with the Harris-Galveston Subsidence District, the Fort Bend Subsidence District, the Lone Star Groundwater Conservation District, and other local partners. This year’s lecture used 2026 water-level altitudes and compared them with the previous year, the previous five years, and the long record back to 1977.
On that 1977 map, he described declines of more than 360 feet, concentrated in south-central Montgomery County. He described rises of more than 180 feet in central Harris County, between Houston and Baytown, and said central and eastern Harris County and Galveston County have seen large water-level rises over the same span.
Those lecture figures line up with the latest published USGS report of the same annual study, Scientific Investigations Report 2025-5028, which Ramage wrote with Alexandra C. Adams. That report uses 2024 measurements. It maps the largest 1977–2024 decline in the Chicot and Evangeline aquifers, treated together, at 360 to 397 feet in south-central Montgomery County. It maps the largest rise over that period at more than 200 feet, up to about 215 feet, in east-central Harris County.
A second long-term map in that report, from 1990 to 2024, puts the largest declines at about 240 to 252 feet, northwest of The Woodlands and in northern Waller County. In the lecture, Ramage pointed to declines of more than 240 feet in northwestern Harris County and southern Montgomery County on that view. The 360-foot drops he described are the south-central Montgomery County pattern, not a northwestern Harris County one.
In 2024, the report also shows the lowest Chicot and Evangeline water-level altitudes, about 300 to 301 feet below the NAVD 88 datum, in small areas in and near The Woodlands. The lowest Jasper altitudes that year, about 250 to 255 feet below datum, sit in south-central Montgomery County and north-central Harris County, again in and near The Woodlands. Jasper measurements in this annual series begin in 2000, so the Jasper long-term map is not a 1977 comparison.
Where levels recovered
Ramage said the rises sit on top of the Harris-Galveston Subsidence District areas that were required to move off groundwater. He said regulatory area 1, southeastern Harris County and Galveston County, has been held to no more than 10 percent groundwater since 1992, and regulatory area 2, through central Harris County, to no more than 20 percent since 2002. On his map, those converted areas coincide with the recoveries.
He was careful about compaction, the squeezing of clay layers underground, and subsidence, the drop in the land surface that compaction helps cause. Extensometers measure compaction between the land surface and the bottom of the instrument. The instruments he showed are in Harris County, plus one in Galveston County. He said the USGS is not running that compaction network in Montgomery County. On the charts, compaction was rapid in the mid-1970s and slowed after the conversion rules, with a clear slowdown around 1992.
The Jasper, and the 200,000 acre-foot proposal
In the question period, a resident asked whether the Jasper is a confined aquifer, with no recharge straight from the surface. Ramage agreed that where the Jasper is buried there is very little direct recharge from above. The published USGS report identifies the Burkeville confining unit as the clay-rich layer that restricts flow between the shallower Chicot and Evangeline aquifers and the Jasper. He said recharge does occur where those sands crop out farther north, and that water moves from higher-pressure areas, including parts of Grimes County, toward the lower-pressure zone under southern Montgomery County. He also said a large share of Montgomery County groundwater production comes from the Jasper, along with continued pumping from the Chicot and Evangeline.
Another speaker said the Lone Star Groundwater Conservation District had concluded the county could go from about 100,000 acre-feet a year to 200,000, and asked how that squares with the declines on the maps. Ramage said he had not been following the proposal. He said the USGS does not take a side in that decision. “We just collect the data,” he said.
The figure the speaker was describing is a desired-future-conditions package in front of Groundwater Management Area 14. Community Impact reported that the package would raise Montgomery County’s modeled available groundwater from 97,000 acre-feet a year to about 199,000, while keeping a goal that a median 70 percent of available drawdown still remain in 2080. On July 9, 2026, Conroe’s city council voted 3–2 to support the proposal. That vote does not, by itself, change pumping permits.
Modeled available groundwater is a planning volume tied to that future-conditions goal. It is a different measure from recharge. The Texas Water Development Board’s GAM Run 24-013, the estimate Lone Star GCD cites in its management-plan review, puts precipitation recharge to the Gulf Coast Aquifer System inside the district at 55,695 acre-feet a year.
Grimes County, and Conroe’s Mid-South deal
An online question asked about large subdivisions in southeast Grimes County. The questioner said established development there uses Mid-South water, which the questioner believes draws from the Jasper, and cited a forecast of about 23,000 single-family homes over five years. Ramage said he was not informed enough about those projects to judge them. He said the practical first step is to keep measuring.
The same day as the lecture, Conroe’s city council authorized the city to buy water and wastewater systems from subsidiaries of Mid-South Electric Cooperative. The city said the assets include 22 water wells, more than 8,000 residential customers, 212 miles of water line, and three wastewater plants, at a price expected around $122.6 million. Mid-South was to keep operating the systems until the Public Utility Commission of Texas approves the transfer. Ramage did not discuss that purchase. The Grimes County question and the Conroe acquisition are separate.
What The Woodlands Green is asking of water providers
After the lecture, The Woodlands Green told state, county, and local leaders that the declines are a reason for every water-producing entity to plan now for well repairs, deeper pumps, and the outages that follow when a well can no longer reach the water. That is the organization’s reading of the maps. It is not a recommendation from the USGS.
The lecture listing is on Woodlands Online. Lecture materials credit Woodlands Water, CenterPoint Energy, and Indorama Ventures.
