Cal. Code Regs. Tit. 22, § 64656 - Disinfection Monitoring

(a) To determine compliance with disinfection inactivation requirements specified in section 64654(a), a supplier shall develop and conduct a monitoring program to measure those parameters that affect the performance of the disinfection process. This shall include but not be limited to the temperature of the disinfected water, the pH(s) of the disinfected water if chlorine is used as a disinfectant, the disinfectant contact time(s) and the residual disinfectant concentration(s) before or at the first customer. The monitoring program shall be described in the operations plan required by section 64661.

(b) To determine compliance with the performance standard specified in section 64654(b)(1), the disinfectant residual concentration of the water being delivered to the distribution system shall be measured and recorded continuously except as provided in subsection (f).

(c) To determine compliance with section 64654(b)(2), the residual disinfectant concentration shall, at a minimum, be measured at the same points in the distribution system and at the same time as total coliforms are sampled in accordance with 22 CCR sections 64423, 64424, and 64425, and described in the operations plan required by section 64661, except as provided in subsection (d).

(d) A supplier that uses both an approved surface water and a groundwater may take disinfectant residual samples at points other than those specified in subsection (c) provided the supplier demonstrates to the State Board that such sampling points are representative of the disinfected water in the distribution system.

(e) If there is a failure of continuous disinfectant residual monitoring equipment, grab sampling every four hours may be conducted in lieu of continuous monitoring, but for no more than five working days following the failure of the equipment.

(f) A supplier serving 3,300 or fewer persons may collect and analyze grab samples of disinfectant residual each day as shown below in lieu of the continuous monitoring specified in subsection (b), provided that any time the residual disinfectant falls below 0.2 mg/L, the supplier shall take a grab sample every four hours until the residual concentration is equal to or greater than 0.2 mg/L:

	System size by population		Samples/day
		less than or equal to 500	1
		501 - 1,000	2
		1,001 - 2,500	3
		2,501 - 3,300	4

(g) A supplier shall describe the location and frequency of sampling to comply with subsection (f) in the operations plan required by section 64661.

Notes

Cal. Code Regs. Tit. 22, § 64656

1. New section filed 5-6-91; operative 6-5-91 (Register 91, No. 25).
2. Amendment of section and NOTE filed 6-8-98; operative 7-8-98 (Register 98, No. 24).
3. Amendment of section heading, section and NOTE filed 5-22-2013; operative 7-1-2013 (Register 2013, No. 21).
4. Change without regulatory effect amending subsection (d) and NOTE filed 6-2-2015 pursuant to section 100, title 1, California Code of Regulations (Register 2015, No. 23).
5. Amendment of subsections (c)-(d) filed 5-28-2021; operative 7-1-2021 (Register 2021, No. 22).

Note: Authority cited: Sections 116271, 116350 and 116375, Health and Safety Code. Reference: Sections 116350, 116375 and 116385, Health and Safety Code.

1. New section filed 5-6-91; operative 6-5-91 (Register 91, No. 25).
2. Amendment of section and Note filed 6-8-98; operative 7-8-98 (Register 98, No. 24).
3. Amendment of section heading, section and Note filed 5-22-2013; operative 7-1-2013 (Register 2013, No. 21).
4. Change without regulatory effect amending subsection (d) and Note filed 6-2-2015 pursuant to section 100, title 1, California Code of Regulations (Register 2015, No. 23).
5. Amendment of subsections (c)-(d) filed 5-28-2021; operative 7/1/2021 (Register 2021, No. 22).