Groundwater
The Ogallala Aquifer is Castro County's water source — and it is declining
Nearly all water in Castro County comes from the Ogallala Aquifer, which has been dropping steadily for decades.
The Ogallala is a huge underground water supply beneath the Texas Panhandle. In Castro County and across the High Plains, it is used overwhelmingly for irrigated farming — the Texas Water Development Board estimates about 95 percent of all pumping goes to irrigated agriculture. The aquifer refills very slowly — less than an inch per year on average. But farmers pump out far more than that. Water levels in Castro County have dropped a lot over recent decades.
If you want to drill a water well, you may need to work with the High Plains Underground Water Conservation District No. 1, known as HPWD. This district covers most of the High Plains, including parts of Castro County, and sets rules for water wells in its territory. You need a permit for any well that can pump 17.5 gallons per minute or more. The HPWD website has permit forms, spacing rules, and pumping limits. The Texas Water Development Board tracks aquifer levels and publishes that data online.
Source to confirm: Texas Water Development Board — Ogallala Aquifer