Section 18.80.415. Repeat monitoring.

	(a)  Except as provided in (b) of this section, if a routine sample is total coliform positive, the operator of a community water system, non-transient non-community water system, or transient non-community water system  
		(1) with more than one service connection shall collect the required number of repeat samples, as provided in (c) of this section, within 24 hours after being notified of the positive result; repeat samples must be collected on the same day;  
		(2) with one service connection and one tap shall collect four repeat samples, or one 400 ml repeat sample within 24 hours after being notified of the positive result; and  
		(3) with one service connection and more than one tap shall collect the required number of repeat samples, as provided in (c) of this section, within 24 hours after being notified of the positive result; all of the repeat samples must be collected on the same day unless the department allows the operator to collect   
			(A) the required number of repeat samples over a four-day period; or  
			(B) a larger volume repeat sample in one or more sample containers of any size in one day; the total volume collected must be at least 400 ml, or at least 300 ml for a system that collects more than one routine sample each month.  
	(b)  The department will extend the 24-hour time limit set in (a) of this section if there is a logistical problem in collecting the repeat samples that is due to unusual and unpredictable circumstances beyond the owner's or operator's control and that makes meeting the 24-hour requirement impossible. For an extension under this subsection, the department will specify how much time the system has to collect repeat samples.  
	(c)  For each total coliform positive sample found during routine sampling, the operator of a community water system, non-transient non-community water system, or transient non-community water system   
		(1) who collects  
			(A) two or more routine samples each month shall collect at least three repeat samples; or  
			(B) one routine sample or less each month shall collect at least four repeat samples; or  
		(2) with one service connection shall collect at least four repeat samples.  
	(d)  The operator of a community water system, non-transient non-community water system, or transient non-community water system shall collect repeat samples as follows:  
		(1) if the system has two or more service connections, the operator shall collect at least one repeat sample from the tap where the original total coliform positive sample was taken, at least one repeat sample from a tap within five service connections upstream of the tap where the original total coliform positive sample was taken, and at least one repeat sample from a tap within five service connections downstream;  
		(2) if the system has one service connection and five or more taps, the operator shall collect at least one repeat sample from the tap where the original total coliform positive sample was taken, at least one repeat sample from the first tap, and at least one repeat sample from a tap within five taps downstream of the tap where the original total coliform positive sample was taken;  
		(3) if the system has one service connection and two to four taps, the operator shall collect at least one repeat sample from the first tap, at least one repeat sample from the last tap, and at least one repeat sample from the tap where the original total coliform positive sample was taken;  
		(4) if the system is classified as a groundwater system subject to 18 AAC 80.800, the operator, in addition to meeting the requirements of (1), (2), or (3) of this subsection, shall meet the requirements of 40 C.F.R. 141.402, adopted by reference in 18 AAC 80.010(a).  
	(e)  If one or more samples in the set of repeat samples required under (a) of this section is total coliform positive and if the MCL for total coliforms in 40 C.F.R. 141.63(a) - (b), adopted by reference in 18 AAC 80.010(a), has not been exceeded, the operator shall  
		(1) collect an additional set of repeat samples as specified in (a) - (d) of this section; the additional samples must be collected within 24 hours after being notified of the positive result, unless the department extends the limit under (b) of this section; and  
		(2) repeat the process required in (1) of this subsection until total coliforms are not detected in one complete set of repeat samples or the department finds that the MCL for total coliforms in 40 C.F.R. 141.63(a) - (b), adopted by reference in 18 AAC 80.010(a), has been exceeded.  
	(f)  If the operator of a community water system, non-transient non-community water system, or transient non-community water system that collects four or fewer routine samples each month has one or more total coliform positive routine samples and the department does not invalidate a sample under 18 AAC 80.425, the operator shall collect routine samples as required by this subsection. During the next month the system provides water to the public, the operator of a system with  
		(1) two or more service connections shall collect five routine samples;  
		(2) one service connection and five or more taps shall collect five routine samples; and  
		(3) one service connection and one to four taps shall collect five routine samples.  
	(g)  The department will waive the requirements of (f) of this section if the conditions described in (1) or (2) of this subsection are met. The department will not waive the requirements of (f) of this section solely because all repeat samples are total coliform negative. The department will waive the requirement in (f) of this section if  
		(1) the department, before the end of the next month the system provides water to the public, conducts a site visit sufficiently detailed to determine whether additional monitoring or corrective action is needed; a system employee may not conduct this site visit even if that employee is an agent approved by the department under 18 AAC 80.435 to conduct sanitary surveys; a site visit under this paragraph is subject to the fee required by 18 AAC 80.1910(a)(1); or  
		(2) the department determines why the sample was total coliform positive and establishes that the system has corrected the problem or will correct the problem before the end of the next month the system serves water to the public; the department will  
			(A) document in writing a decision under this paragraph to waive the following month's additional monitoring requirement;  
			(B) have the decision approved and signed by the supervisor of the department official who recommended the decision;  
			(C) make the decision available to EPA and the public; and  
			(D) describe the specific cause of the total coliform positive sample and describe what action the owner of the system has taken or will take to correct that problem.  
	(h)  If the department waives the requirements of (f) of this section under (g)(2) of this section, the operator shall take at least one routine sample before the last day of the next month the system serves water to the public unless the department finds that the owner or operator corrected the problem before the operator took the repeat samples required under (a) - (e) of this section and all repeat samples were total coliform negative.  
	(i)  If, before learning the analytical results of a routine sample that is found to contain total coliform, the operator collects a subsequent routine sample from within five adjacent service connections of the initial sample, the operator may count the subsequent sample as a repeat rather than a routine sample.  

Authorities

46.03.020;46.03.050;46.03.710;46.03.720

Notes

Reference

18 AAC 34.080
18 AAC 80.410
18 AAC 80.425

Authority

AS 46.03.020 AS 46.03.050 AS 46.03.710 AS 46.03.720

History

Eff. 10/1/99, Register 151; am 4/24/2009, Register 190; am 7/25/2010, Register 195; am 5/20/2011, Register 198