If you've ever tried to dig a post hole in parts of Corpus Christi and hit something like concrete a foot or two down, you've met caliche. Wikipedia describes the city as sitting on river-laid deposits, including the Deweyville Formation of sand, silt, clay and gravel, locally cemented with calcium carbonate: caliche.
What it means for a fence
- Slower digging. Hand diggers bounce off it; installers may need a powered auger with a rock bit, or a breaker.
- Higher labor. More time per hole shows up in the quote.
- Good holding power. Once a post is set in a hole cut into caliche, it can be very solid.
- Drainage. Water may sit on top of a hard layer, so a post bottom can stay wet.
Tips
- Ask if the installer probes a few holes before the final price, or how they price rock.
- Call 811 first. Texas811 asks for two business days' notice before any digging.
- Don't shorten posts to avoid digging; in this wind a shallow post is the first to fail.
Near the water
Where a lot is loose sand instead, digging is easy but the soil doesn't grip a post as tightly, and concrete footings help.
Sources
Checked November 10, 2026. City rules and price surveys change; trust the linked original.