What about aquifers that cross state and international lines?

They are managed by cooperation, the same tool used for shared rivers, and that cooperation continues at independence. Aquifers that cross borders are a common feature among neighboring states and nations, and nothing about independence requires Texas to drain or surrender a drop.

Some Texas groundwater is shared, and that is already true today

Groundwater does not stop at a survey line. The Ogallala, part of the larger High Plains Aquifer that sits beneath the Texas Panhandle, also underlies seven other states. Along the border, aquifers like the Hueco Bolson and the Mesilla Basin extend beneath Texas, New Mexico, and the Mexican state of Chihuahua, supplying cities including El Paso and Ciudad Juarez. Shared groundwater is not a new problem created by independence. It is a present-day fact that Texas already lives with.

Texas manages its own groundwater locally

Inside Texas, groundwater is managed under Texas law, primarily through local groundwater conservation districts working within the state planning framework. That structure is entirely Texan and does not depend on Washington. It keeps running at independence exactly as it runs now, setting local rules for how much can be pumped and protecting the resource for the long term.

Cross-border aquifers are handled cooperatively, between sovereigns

Where an aquifer crosses into another state or country, the tool is cooperative management, the same approach used for shared rivers. The United States and Mexico already study the border aquifers together through a binational assessment program. After independence, that kind of cooperation simply continues between sovereign neighbors, the way shared groundwater is managed cooperatively in many parts of the world. Texas would participate directly, as the party that actually shares the water, rather than through a federal intermediary.

Independence does not require Texas to give anything up

There is no mechanism by which a change of sovereignty drains a Texas aquifer or transfers Texas groundwater to anyone. Texas keeps its own groundwater law, keeps its local conservation districts, and keeps its place in the cooperative arrangements for the aquifers it shares. The water beneath Texas stays governed by Texans, and the shared water stays governed by agreement.

The bottom line

Shared aquifers follow the same logic as shared rivers. Texas keeps managing its own groundwater under Texas law, the cross-border aquifers stay under cooperative agreements, and independence gives Texas a direct voice in that cooperation. Nothing about it requires Texas to surrender its water.