1. (a) A responsible party must conduct an investigation of the unauthorized release, the source area, and the surrounding area possibly affected by the unauthorized release, if any of the following conditions exist:

   1. (1) There is evidence that surface water or groundwater has been or may be affected by the unauthorized release;
   2. (2) Free product is found at the site where the unauthorized release occurred or in the surrounding area;
   3. (3) There is evidence that contaminated soils are or may be in contact with surface water or groundwater; or
   4. (4) The Cleanup Oversight Agency directs an investigation, based on the actual or potential effects of contaminated soil or groundwater on nearby surface water or groundwater resources or based on the increased risk of fire or explosion.
2. (b) The Soil and Water Investigation Phase includes the collection and analysis of data necessary to assess the full nature and vertical and lateral extent of the unauthorized release and to determine a cost-effective method of cleanup for the purpose of promoting prompt cleanup and closure consistent with all applicable state policies for water quality control adopted pursuant to article 3 (commencing with section 13140) of chapter 3 of division 7 of the Water Code.

Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25296.10 and 25296.15, Health and Safety Code; and 40 CFR Section 280.65.

History

1. Repealer and new section filed 8-9-91 as an emergency; operative 8-9-91. Text remains in effect uninterrupted pursuant to Health and Safety Code section 25299.7 (Register 92, No. 14).

2. Editorial correction of printing errors in History 1 (Register 92, No. 43).

3. Amendment filed 4-5-94; operative 5-5-94 (Register 94, No. 14).

4. Amendment of section heading, section and Note filed 5-13-2004; operative 6-12-2004 (Register 2004, No. 20).

5. Amendment of subsections (c) and (c)(4), repealer of subsection (c)(5), subsection renumbering and new subsection (d) filed 12-18-2007; operative 1-17-2008 (Register 2007, No. 51).

6. Amendment of section and Note filed 10-13-2016; operative 1-1-2017 (Register 2016, No. 42).

7. Amendment filed 8-27-2020; operative 10-1-2020 (Register 2020, No. 35). Filing deadline specified in Government Code section 11349.3(a) extended 60 days pursuant to Executive Order N-40-20 and an additional 60 days pursuant to Executive Order N-66-20.

8. Repealer and new section heading and section filed 10-28-2025; operative 1-1-2026 (Register 2025, No. 44).