The Trinity Edwards Springs Protection Association (TESPA) has filed a formal complaint with the Public Utility Commission of Texas (PUC) over practices employed by Aqua Texas, the association announced Wednesday.

TESPA claims the company serves its customers with an illegal groundwater supply. The filing requests that the PUC either revoke Aqua Texas’ authority to provide water in the Wimberley area or mandate significant changes to its operations.

Read more from Johann Castro and Jenni Lee with KVUE here.