Analytical requirements for groundwater source microbiological contaminants

Analytical requirements for groundwater source microbiological contaminants. (1) Analytical methods. (a) A water supplier for a groundwater system subject to the source water monitoring requirements of s. NR 809.325 (2) shall collect a standard sample volume of at least 100 mL for E. coli analysis regardless of the analytical method used. (b) A water supplier for a groundwater system shall analyze all groundwater source samples, collected under s. NR 809.325 (2) , using one of the analytical methods listed in Table G for the presence of E. coli . If the department requires a public water system to be tested for the presence of enterococci or coliphage, the water supplier shall use one of the methods listed in Table G. (c) Sample volumes of at least 100 mL shall be used for all analyses using the methods in Table G. Analyses shall be conducted in accordance with the documents listed in the footnotes to Table G. (d) The sample holding time shall not exceed 30 hours. In all cases, samples should be analyzed as soon after collection as possible. (2) Invalidation of an E. coli -positive groundwater source sample. (a) The department may invalidate an E. coli -positive groundwater source sample collected under s. NR 809.325 (2) under the conditions specified in subd. 1. or 2. 1. The water supplier provides the department with written notice from the laboratory that improper sample analysis occurred. 2. The department determines and documents in writing that there is substantial evidence that an E. coli -positive groundwater source sample is not related to source water quality. (b) If the department invalidates an E. coli -positive groundwater source sample, the water supplier shall collect another source water sample under s. NR 809.325 (2) no later than 24 hours after being notified by the department that the sample has been invalidated. The water supplier shall have the sample analyzed for E. coli using the analytical methods in s. NR 809.323 (1) (b) Table G. (c) The department may extend the 24-hour time limit on a case-by-case basis if the water supplier cannot collect the source water sample within the 24-hour time limit due to circumstances beyond the water supplier’s control. In the case of an extension, the department shall specify in writing how much time the water supplier has to collect the sample.