Section 18.80.425. Invalidation of total coliform samples.

	(a)  A total coliform positive sample invalidated under this section may not be counted toward meeting the minimum monitoring requirements of 18 AAC 80.405 - 18 AAC 80.415. The department will not invalidate a total coliform positive sample because all repeat samples are total coliform negative. However, the department will invalidate a total coliform positive sample if  
		(1) the certified laboratory that performed that analysis establishes the improper sample analysis caused the total coliform positive result;  
		(2) the department, based on the results of repeat samples collected under 18 AAC 80.415(a) - (e), finds that the total coliform positive sample resulted from a domestic or other nondistribution system plumbing problem; the department will not invalidate a sample on the basis of repeat sample results  
			(A) unless all repeat samples collected at the same tap as the original total coliform positive sample are also total coliform positive and all repeat samples collected within five service connections of the original tap are total coliform negative; or  
			(B) if the community water system, non-transient non-community water system, or transient non-community water system has only one service connection; or  
		(3) the department has substantial grounds to determine that a total coliform positive result is due to a circumstance or condition that does not reflect water quality in the distribution system; the operator must collect all repeat samples required under 18 AAC 80.415(a) - (e) and use them to determine compliance with the MCL for total coliforms in 40 C.F.R. 141.63(a) - (b), adopted by reference in 18 AAC 80.010(a).  
	(b)  If the department invalidates a total coliform positive sample under (a) of this section, the department will  
		(1) document the decision in writing;  
		(2) make the decision available to the EPA and the public; and  
		(3) describe the specific cause of the total coliform positive sample and what action the owner or operator of the system has taken or will take to correct that problem.  
	(c)  The certified laboratory performing a total coliform analysis shall invalidate a sample in which total coliforms are not detected, if the sample produces  
		(1) a turbid culture in the absence of gas production using an analytical method where gas formation is examined;  
		(2) a turbid culture in the absence of an acid reaction in the presence-absence coliform test; or  
		(3) confluent growth or colonies too numerous to count with an analytical method using a membrane filter.  
	(d)  If a certified laboratory invalidates a sample under (c) of this section, the laboratory shall notify the department and the owner by telephone or facsimile within 24 hours after invalidating the sample. The operator shall collect another sample from the same location as the original sample within 24 hours after being notified of the invalidation and shall have the new sample analyzed for the presence of total coliforms. If the laboratory invalidates the new sample or a subsequent sample, the operator shall continue to re-sample within 24 hours after receiving notification of the invalidation and shall have the samples analyzed until a valid result is obtained. The department will waive the 24-hour time limit if the department determines that public health is adequately protected.  

Authorities

46.03.020;46.03.050;46.03.070;46.03.710;46.03.720

Notes

Reference

18 AAC 34.080
18 AAC 80.035
18 AAC 80.305
18 AAC 80.415
18 AAC 80.655

Authority

AS 46.03.020 AS 46.03.050 AS 46.03.070 AS 46.03.710 AS 46.03.720

History

Eff. 10/1/99, Register 151; am 4/24/2009, Register 190