Dig far enough in much of southern Arizona and you'll hit a pale, hard layer that the shovel bounces off. That's caliche, and it's behind a lot of surprise line items on excavation quotes.
What it is
The University of Arizona's Cooperative Extension describes caliche as soil cemented together by lime (calcium carbonate). It usually shows up as a light-colored layer, or as white or cream-colored lumps. Many southern Arizona soils have caliche layers, and they range from a few inches to several feet thick.
Why it matters for excavation
- Slow digging. Angi's Phoenix guide describes hard, compacted caliche that needs heavy-duty breakers, and lists soil-type work at $210 to $1,240 extra.
- Unknown until you dig. Angi's pool guide notes the extent of rock may not be known until digging starts. Quotes often price it as a contingency.
- Drainage. Extension notes that caliche slows water movement, so water can sit above it.
Drainage test
Extension suggests partly filling a hole with water: a drop of 4 inches or more in four hours means adequate drainage. Where water sits, it recommends digging through the caliche so water can drain. If that isn't practical, dig a smaller drainage hole through the layer.
For yards and landscaping
Extension recommends at least 8 inches of good topsoil above caliche for lawns, and notes that a solid layer can stop roots from getting through. When a yard is being regraded anyway, that's a good time to deal with shallow caliche.
Questions for your contractor
- Have you dug on this street or subdivision before? What did you find?
- What's the rate or allowance if you hit caliche?
- Will broken caliche be hauled off or reused as fill?
Sources
- University of Arizona Cooperative Extension: Caliche Quick Guide (July 2025)
- Angi: Excavation costs in Phoenix, AZ (updated June 16, 2026)
- Angi: How much does pool excavation cost? (Scott Dylan Westerlund, updated October 19, 2026)
Reviewed October 20, 2026. Rules, prices and contacts change, so check the source before relying on it.
Questions and answers
What is caliche?
The University of Arizona describes caliche as soil cemented together by lime (calcium carbonate), usually a light-colored layer from a few inches to several feet thick, common in southern Arizona soils.
Does caliche make a pool dig cost more?
Often. Angi's pool guide prices rocky ground at $40 to $100 per cubic yard against $8 to $25 for dirt, and its Phoenix guide says caliche can need heavy-duty breakers.
Get it quoted
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