This has become a complicated issue. To understand the current regulations you need to consider written regulations, intent, recapture clauses, and contact with regulatory officials.
Here is the written regulations that occur in the Possession and Transportation of Exotic Aquatic Species. The section starts with, “The intentional or unintentional possession or transportation of aquatic invasive species without a permit is illegal in Texas.” So the intent of the bait regulations is to prevent to movement of invasive species, such as zebra mussels, from one waterbody to another.
Here are the regulations pertaining to,bait:
Mandatory Draining of Water from Vessels
Persons leaving or approaching public fresh water are required to drain all water from their vessels and on-board receptacles (includes live wells, bilges, motors and any other receptacles or water-intake systems coming into contact with public waters). This rule applies at all sites where boats can be launched and includes all types and sizes of boats whether powered or not, personal watercraft, sailboats, kayaks/canoes, or any other vessel used to travel on public waters.
Live fish, including personally caught live bait, cannot be transported from the water body where the fish were caught in or aboard a vessel in water from the water body where the fish were caught. Personally caught live bait can be used in the water body where it was caught.
Transport and use of commercially purchased live bait in water while fishing from a vessel is allowed, provided persons in possession of the bait have a receipt that identifies the source of the bait. Any live bait purchased from a location on or adjacent to a public water body that is transported in water from that water body can only be used as bait on that same water body.
A vessel leaving a public freshwater body may be transported on a public roadway without water being drained, provided the vessel is transported via the most direct route to another access point located on the same water body during that same day.
Persons participating in a fishing tournament confined to one water body are allowed to transport live fish in water from that single water body to an identified off-site weigh-in location, provided all water is drained and properly disposed of before leaving that location. Participants must possess documentation provided by tournament organizers that identify them as participants in a tournament.
Marine sanitary systems are not covered by these regulations.
(And then an additional recapture clause):
Following these procedures does not exempt persons from complying with prohibitions against transporting exotic aquatic species that are visible to the unaided eye, such as adult zebra mussels, which may be attached to boats or trailers.
The current loop hole occurs in this part of the regulation.
Live fish, including personally caught live bait, cannot be transported from the water body where the fish were caught in or aboard a vessel in water from the water body where the fish were caught. Personally caught live bait can be used in the water body where it was caught.
Since the first part states that bait cannot be transported IN WATER from a waterbody, they believe that if they bring their own water the can transport bait from one waterbody to another. I know some guides do this regularly. They ignore the next sentence in the regulations, which has the intent of saying you can only use live bait from the water where it was caught.
So, even if you bring your own water and you inadvertently (intentionally or unintentionally) transport or possess an invasive species you are in violation.
Game Warden interpretations vary on this issue.
To be sure you are legal, keep a bait receipt and don’t transfer bait from one waterbody to the other.
Sorry for the long post, but I could have made it much longer. There are many more variations we could discuss.