Water Code § 13176
ARTICLE 4. Other Powers and Duties of the State Board
(a) (1) The analysis of any material required by this division shall be performed by a laboratory that has accreditation or certification pursuant to Article 3 (commencing with Section 100825) of Chapter 4 of Part 1 of Division 101 of the Health and Safety Code.
(2) This requirement does not apply to field tests, such as tests for color, odor, turbidity, pH, temperature, dissolved oxygen, conductivity, and disinfectant residual.
(b) A person or public entity of the state shall not contract with a laboratory for environmental analyses required by paragraph (1) of subdivision (a) unless the laboratory has valid accreditation or certification.