The grading permit conditions and the geotechnical report both require testing and inspection during earthwork operations. This is not optional quality assurance — it is a legal requirement that the building department enforces. Without the testing and inspection documentation (the compaction report), you will not receive grading completion approval, and without grading completion, you cannot pull the building permit on most projects.

The Inspection and Testing Team

The geotechnical firm that prepared the project's geotechnical report typically provides the field inspection and testing services during grading. This is intentional — the firm that set the design parameters is best positioned to verify that construction meets those parameters. The key personnel are:

• Geotechnical engineer of record — the licensed PE who signed the geotechnical report. They oversee the inspection program, review test results, and certify that the grading complies with their recommendations.
• Field technician — a trained technician (typically certified by ICC, NICET, or the ACI) who performs the daily field testing and inspection. They report to the geotechnical engineer.
• Special inspector — for certain conditions (e.g., reinforced masonry retaining walls, drilled piers), a special inspector may be required in addition to the grading inspector.

What Gets Tested and When

During Fill Placement

• Material classification: The field technician classifies every soil type used as fill (USCS classification, visual description, moisture content). Material that does not meet the specifications for fill (organic content too high, rock too large, contaminated) is rejected.
• Maximum dry density (Proctor test): A laboratory Proctor test (ASTM D1557, Modified Proctor) is performed on each soil type used as fill. This test produces the maximum dry density and optimum moisture content, which become the reference values for all field compaction tests. Typically, one Proctor test is performed per 1,000 to 5,000 cubic yards of fill, or whenever the fill material type changes.
• In-place density tests: Nuclear density gauge tests at the frequency specified by the geotechnical engineer — typically one test per 2 feet of fill height per 2,500 to 5,000 square feet of area. Each test is compared to the Proctor reference values.
• Lift thickness verification: The field technician verifies that each lift does not exceed the maximum loose thickness (typically 8 inches loose, 6 inches compacted).

At Subgrade

• Proof rolling: As described in the subgrade preparation article — the entire subgrade is proof-rolled and evaluated for soft spots.
• Final density tests: Tests at the finished subgrade elevation to confirm the required compaction has been achieved.
• R-value testing (if not previously performed): If the geotechnical report did not include R-value testing of the subgrade soil, it must be performed at this stage to finalize the pavement section design.

During Utility Trenching

• Bedding inspection: Verify that the pipe bedding material and thickness meet specifications before the pipe is placed.
• Backfill compaction: Density tests at each lift of trench backfill, at the frequency specified in the project specifications.
• Pipe pressure testing: Water mains and fire mains are pressure-tested per AWWA standards to verify joint integrity and absence of leaks. Sewer mains are tested for infiltration/exfiltration per the sewer district's standards.

Hold Points

A hold point is a stage of construction where work must stop until the inspector approves the preceding work. Common grading hold points:

Hold Point	What Must Be Approved
Bottom of over-excavation	The excavated surface is at the specified depth and competent material has been exposed
Top of keyway	The keyway (for fill slopes) is at the correct depth, width, and gradient, and is properly benched
Finished subgrade	Compaction tests pass, proof roll is satisfactory, subgrade is ready for aggregate base or slab
Top of aggregate base	Base is at the correct thickness, compacted to specification, and graded to plan
Pipe bedding	Bedding material is correct, at the proper depth, and the pipe can be placed
Top of trench backfill	All lifts have been tested and pass, and the trench is ready for pavement restoration

The contractor must call for inspection at each hold point with at least 24 hours' notice (typical). Proceeding past a hold point without inspection is a violation of the grading permit and may require the work to be removed and redone under inspection.

The Compaction Report

At the completion of grading, the geotechnical engineer compiles all field inspection notes, test results, and laboratory data into a compaction report (also called a grading completion report). This report certifies that:

• Grading was performed in substantial conformance with the approved grading plans and the geotechnical report recommendations
• All fill was compacted to the required relative compaction
• All subgrades were prepared as specified
• All utility trench backfill was compacted as specified
• Any deviations from the plans or recommendations were documented and evaluated for acceptability

The compaction report is submitted to the building department as a condition of grading completion. Without it, the grading is not officially complete, and subsequent permits (building permit, occupancy permit) may not be issued.

Cost

Geotechnical inspection and testing during grading is typically billed at $75 to $150 per hour for the field technician and $150 to $300 per hour for the geotechnical engineer's time. Laboratory testing (Proctor, gradation, expansion index) is billed per test at $150 to $500 each. For a typical commercial project with 2 to 4 weeks of earthwork, the total inspection and testing cost is $10,000 to $40,000. This is a required cost — budget for it from the beginning.