Why pricing is hard to find online
Most geotechnical firms don't publish compaction testing rates. There's a reason for that: the cost varies significantly based on project size, test frequency, location, and how the work is scoped. A single-family home in San Diego and a commercial grading project in Riverside have nothing in common from a cost standpoint.
We're going to give you real numbers — because we think you deserve to know what you're paying for before you call anyone.
How compaction testing is typically priced
There are two main pricing structures in Southern California:
Per-test (unit) pricing: You pay for each nuclear gauge density test performed. Rates typically run $35–$65 per test in Southern California, depending on the firm and the project. There's usually a minimum charge per mobilization.
Daily rate (field technician time): For larger projects with continuous grading, you pay a daily rate for a field technician who performs tests throughout the day. Daily rates for a compaction technician typically run $600–$950 per day in Southern California, including equipment and a set number of tests.
For most residential projects (single-family homes, ADUs, small commercial), per-test pricing is standard. For large grading operations with multiple days of continuous oversight, daily rates are more efficient.
Working on a project in Southern California? We can handle the engineering.
Typical total costs by project type
Single-family home on flat lot (standard fill, 2–4 feet depth): 8–20 tests total, $350–$1,200 in testing costs. Add mobilization fees ($150–$250 per site visit) if the testing spans multiple days.
Detached ADU with new foundation pad: 4–12 tests, $250–$750 total. Often completed in 1–2 site visits.
Hillside home with cut-and-fill pad (deeper fill, more complex): 20–50+ tests over multiple grading phases, $1,500–$4,500+. Slope conditions mean more test locations and deeper fill that requires more lift-by-lift verification.
Commercial pad grading (parking lot, building pad, 1–2 acres): $3,000–$10,000+ over the full grading operation. Larger sites have more area to cover; commercial specs often require 95% compaction (vs. 90% for residential), which means more thorough testing.
Large grading project (subdivision, 5+ acres): $15,000–$50,000+ depending on grading duration. Full-time or near-full-time technician presence throughout.
What affects where your project falls in the range
Depth of fill. More fill = more lifts = more tests. A 2-foot building pad gets maybe 4 test elevations. A 15-foot fill pad gets 15+ elevations.
Compaction specification. 90% compaction is standard for most residential fill. 95% is required under slabs, pavement, and structural fill — and means any marginal areas are more likely to fail and require retesting.
Soil type. Cohesive soils (clays, silts) are harder to compact and more likely to fail tests than granular soils (sands, gravels). Problem soil = more retests.
Site access and travel time. Projects more than 30–45 minutes from our office may carry a travel charge, or we schedule multiple site visits on the same trip to keep costs down.
Contractor quality. This matters more than people realize. A skilled grading contractor who knows how to compact properly the first time — right moisture content, right lift thickness, right equipment — will pass tests consistently. A contractor who skips steps or brings in the wrong soil will fail frequently and drive up retesting costs.
What you're actually getting with compaction testing
Compaction testing isn't just a permit requirement. It's field verification that the dirt under your foundation is actually solid. Poorly compacted fill settles unevenly, and settlement means cracked foundations, tilted slabs, and doors that won't close.
The cost of proper compaction testing on a $50,000 foundation is a rounding error. The cost of foundation repairs from poor compaction — underpinning, slab grinding, structure leveling — runs $20,000–$100,000+.
If you're getting bids on compaction testing, make sure you're comparing the same scope. Some firms quote per-test with no mobilization minimum; some bundle tests in day rates. Ask for a written scope before you sign.
Related Service
Compaction Testing & Observation
We handle this for projects across Southern California.
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