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Section 64424. Repeat sampling <br />(c) <br />(1)(1) The Department conducts a site visit before the end of the next month the system provides water to <br />the public to determine whether additional monitoring and/or corrective action is necessary to protect public <br />health. <br />California Code of Regulations <br />Title 22 <br />Division 4 <br />Chapter 15 <br />If one or more samples in the repeat sample set is total coliform-positive, the water supplier shall collect <br />and have analyzed an additional set of repeat samples as specified in subsections (a) and (b). The supplier shall <br />repeat this process until either no coliform are detected in one complete repeat sample set or the supplier determines <br />that the MCL for total coliform specified in Section 64426.1 has been exceeded and notifies the Department. <br />(a) If a routine sample is total coliform-positive, the water supplier shall collect a repeat sample set as <br />described in paragraph (a)(1) within 24 hours of being notified of the positive result. The repeat samples shall all be <br />collected within the same 24 hour time period. A single service connection system may request that the Department <br />allow the collection of the repeat sample set over a four-day period. <br />(2) The Department determines why the sample was total coliform-positive and establishes that the <br />system has corrected the problem or will correct the problem before the end of the next month the system <br />serves water to the public. If a waiver is granted, a system shall collect at least one routine sample before <br />the end of the next month it serves water to the public and use it to determine compliance with Section <br />64426.1. <br />(b) When collecting the repeat sample set, the water supplier shall collect at least one repeat sample from the <br />sampling tap where the original total coliform-positive sample was taken. Other repeat samples shall be collected <br />within five service connections upstream or downstream of the original site. At least one sample shall be from <br />upstream and one from downstream unless there is no upstream and/or downstream service connection. <br />(1) For a water supplier that normally collects more than one routine sample a month, a repeat sample <br />set shall be at least three samples for each total coliform-positive sample. For a water supplier that normally <br />collects one or fewer samples per month, a repeat sample set shall be at least four samples for each total <br />coliform-positive sample. <br />(d) If a public water system for which fewer than five routine samples/month are collected has one or more total <br />coliform-positive samples, the water supplier shall collect at least five routine samples the following month. If the <br />supplier stops supplying water during the month after the total coliform-positive(s), at least five samples shall be <br />collected during the first month the system resumes operation. A water supplier may request the Department waive <br />the requirement to collect at least five routine samples the following month, but a waiver will not be granted solely <br />on the basis that all repeat samples are total coliform-negative. To request a waiver, one of the following conditions <br />shall be met: <br />(2) If the water supplier is unable to collect the samples within the 24-hour time period specified in <br />subsection (a) or deliver the samples to the laboratory within 24 hours after collection because of <br />circumstances beyond its control, the water supplier shall notify the Department within 24 hours. The <br />Department will then determine how much time the supplier will have to collect the repeat samples.