1. (a) An OTNWS using a pathogen control treatment train in accordance with section 60632 is exempt from the requirements of this section.
2. (b) Each treatment process used to meet the pathogen log reduction targets in Table 60630-1 must be validated for pathogen log reduction or inactivation. A validation study report must be submitted to the local jurisdiction for review and approval. The validation study report must follow a validation study protocol approved by the local jurisdiction.
3. (c) Local jurisdictions must consult with the State Board prior to approving the validation study protocol and validation study report.
4. (d) The validation study protocol and report must be prepared by a California licensed engineer, with at least five (5) years of experience as a licensed engineer in drinking water or wastewater treatment evaluating treatment processes for pathogen control. A UV disinfection process validation study report may be prepared by an engineer licensed in a state other than California as long as the other qualifications in this subsection are met.

5. (e) The validation study report must demonstrate that the proposed treatment process and the overall treatment train provides reliable and continuously verifiable pathogen removal and must contain the following information:

   1. (1) A validation study protocol prepared in accordance with subsection (f) and approved by the local jurisdiction;
   2. (2) A summary of the log reduction value demonstrated by each treatment process for each pathogen identified in subsection (f)(2), the operating envelope, and the critical limit(s) for each validated treatment process; and
   3. (3) Evidence of the treatment technology's ability to achieve the pathogen log reduction value reliably and consistently, including information on the required operating conditions and surrogate parameters proposed for continuous process verification monitoring.

6. (f) A validation study protocol must:

   1. (1) Identify the treatment mechanism(s) of pathogen reduction by the treatment process;
   2. (2) Identify the pathogen(s) being addressed by the treatment, or appropriate surrogate(s) for the pathogen(s), that are used in the validation study. The pathogen(s) and surrogate(s) selected for the validation study shall be the one(s) most resistant to the treatment mechanisms;
   3. (3) Ensure that the pathogen(s) or surrogate(s) are present in the test water in concentrations sufficient to demonstrate a pathogen log reduction;
   4. (4) Identify the factors that influence the pathogen reduction efficiency for treatment mechanism(s). Influencing factors include, but are not limited to, feed water characteristics such as temperature and pH, hydraulic loading, deterioration of components, and integrity failure;
   5. (5) Identify the surrogate and/or operational parameters that can be measured continuously and that will correlate with the reduction of the pathogen(s) or surrogate(s) for the pathogen(s).
   6. (6) Identify the validation methodology to demonstrate the capability of the treatment process. The validation methodology shall involve a challenge test to quantify the reduction of the target pathogen or appropriate surrogate while concurrently monitoring the operational parameters to determine an operating envelope;
   7. (7) Describe the method to collect and analyze data to formulate evidence-based conclusions;
   8. (8) Describe the method to determine the critical limit(s) and the operational monitoring and control strategy;
   9. (9) Describe the method to be used to calculate the log reduction value for the treatment process for each pathogen. The validated log reduction value shall not exceed that achieved by 95 percent of the challenge test results when the treatment process is operating in compliance with the critical limit(s); and
   10. (10) Identify the circumstances that would require a re-validation or additional onsite validation, including but not limited to, when conditions are inconsistent with the previous validation test conditions.

Note: Authority cited: Sections 13558 and 13558.1, Water Code; and Sections 116271 and 116350, Health and Safety Code. Reference: Sections 13558 and 13558.1, Water Code.

History

1. New section filed 4-22-2026; operative 4-22-2026 pursuant to Water Code section 13558(f) (Register 2026, No. 17).