Chapter 3. Backfilling Excavations With Native Spoil of California Government Code >> Division 5. >> Title 1. >> Chapter 3.

As used in this chapter:
  (a) "Competent spoil" means soils that can be treated to bring their moisture content into the optimum range, and that can achieve the compaction required by the city or county in whose jurisdiction an excavation is located.
  (b) "Excavation" means any operation in which earth, rock, or other material in the ground is moved, removed, or otherwise displaced by means of tools, equipment, or explosive in any of the following ways: grading, trenching, digging, ditching, drilling, augering, tunneling, scraping, pipe plowing and driving, or any other way.
  (c) "Local agency" means any city, county, city and county, special district, school district, or other political subdivision of the state.

Any local agency that undertakes or contracts for an excavation for the installation, removal, maintenance, or repair of underground facilities may backfill that excavation in any local agency public road or highway with native spoil if the conditions in subdivisions (a), (b), and (c) are met. Where the excavation is performed by contract, use of native spoil shall be permitted unless otherwise specified in the contract documents.
  (a) The native spoil is competent spoil.
  (b) Compaction meets the local agency's requirements, using industry standards for testing compaction.
  (c) The local agency or its contractor has no physical evidence of, or substantial reason to believe that there has been, contamination of the soil from hazardous waste.