R 325.10704b Total coliform; analytical methods.

Rule 704b. (1) All of the following provisions apply to analytical methodology for compliance with the total coliform rules in R 325.10704a. (a) The standard sample volume required for analysis, regardless of analytical method used, is 100 milliliters. (b) Supplies need only determine the presence or absence of total coliforms and E. coli; a determination of density is not required. (c) The time from sample collection to initiation of test medium incubation shall not exceed 30 hours. Supplies are encouraged but not required to hold samples below 10 degrees Celsius (50 degrees Fahrenheit) during transit. (d) If water having residual chlorine (measured as free, combined, or total chlorine) is to be analyzed, sufficient sodium thiosulfate (Na2S2O3) shall be added to the sample bottle before sterilization to neutralize the residual chlorine in the water sample. Dechlorination procedures are addressed in Section 9060A.2 of Standard Methods for the Examination of Water and Wastewater (20th and 21st editions), which is adopted by reference in R 325.10605. (e) Supplies shall conduct total coliform and E. coli analyses in accordance with the appropriate analytical methods adopted by reference in R 325.10605. (2) Supplies shall have all compliance samples required under the total coliform rules R 325.10704a to R 325.10704k analyzed by a laboratory certified by the EPA or the department to analyze drinking water samples, as required under R 325.10601a and R 325.10731. The laboratory used by the supply shall be certified for each method (and associated contaminant(s)) used for compliance monitoring analyses under total coliform rules, R 325.10704a to R 325.10704k. (3) The standards required in these rules are incorporated by reference in R 325.10605.