I second what Rainman said. If the pond was a feature of the property (in other words the fact that the property had a pond became part of the purchase decision) then I would have the pond looked at by a professional.

I don't know anything about Texas (except for the fact that I have friends there and the state is huge) but in California you can lose 7 to 8 feet of water just through evaporation during the dry months (in Northern California that is typically May through October). So in Northern California you must plan for that level of evaporation.

The loss could be due to an improperly sealed pond, inadequate watershed, evaporation, leaking dam, or a combination of these factors and probably several other things that I can't think of.

Hang on for expert feedback (as opposed to my idol speculation).

Welcome to Pond Boss, we're glad you found us.

JHAP
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"My mind is a raging torrent, flooded with rivulets of thought cascading into a waterfall of creative alternatives."
...Hedley Lamarr (that's Hedley not Hedy)