§ 64536.4. Disinfection Byproduct Precursor Compliance Calculations.

(a) Systems not meeting any of the criteria identified in sections 64536(a) or (b) shall comply with requirements contained in sections 64536.2(a) or (b) and shall calculate compliance quarterly, beginning after the system has collected 12 months of data, by determining an annual average using the following method:

(1) Determine actual monthly TOC percent removal, equal to:

(1 - [treated water TOC/source water TOC]) x 100.

(2) Determine the required monthly TOC percent removal (from either table 64536.2-A or from section 64536.2(c)).

(3) Divide the value in paragraph (a)(1) by the value in paragraph (a)(2).

(4) Add together the results of paragraph (a)(3) for the last 12 months and divide by 12.

(5) If the value calculated in paragraph (a)(4) is less than 1.00, the system is not in compliance with the TOC percent removal requirements.

(b) In any month that one or more of the conditions of sections 64536.4(b)(1) through (b)(6) are met, the system may assign a monthly value of 1.0 (in lieu of the value calculated in section 64536.4(a)(3)) when calculating compliance under the provisions of subsection (a).

(1) The system's source water TOC level, prior to any treatment, is less than or equal to 2.0 mg/L.

(2) The system's treated water TOC level is less than or equal to 2.0 mg/L.

(3) The system's source water SUVA, prior to any treatment, is less than or equal to 2.0 L/mg-m.

(4) The system's finished water SUVA is less than or equal to 2.0 L/mg-m.

(5) A system practicing softening removes at least 10 mg/L of magnesium hardness (as CaCO₃).

(6) A system practicing enhanced softening lowers alkalinity below 60 mg/L (as CaCO₃).

HISTORY

1. New section filed 5-18-2006; operative 6-17-2006 (Register 2006, No. 20).

Note

Note: Authority cited: Sections 116325, 116370 and 116375, Health and Safety Code. Reference: Sections 116350, 116385 and 116555, Health and Safety Code.