Texas Porch
Groundwater Practical

Dallas County Sits Over the Trinity Aquifer

Dallas County Home & Property

The Trinity Aquifer lies under Dallas County and 60 other Texas counties. Across North Texas, its fresh-water layers average about 600 feet thick. That is a broad area figure, not a reading for one tract. TWDB has also found large past drops in water levels along I-35. City pumping caused most of that drop.

Near the aquifer's outcrop, water can be fresh but very hard. Water often gets saltier with depth. If land has a private well, check that well's depth and records. Test the water too. Use the TWDB map for the big picture, but do not apply an area average to one well.

Content last revised 2026-07-11

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