WAC 246-290-320   Follow-up action.  (1) General.

     (a) When an MCL or MRDL violation or exceedance occurs, the purveyor shall take follow-up action as described in this section.

     (b) When a primary standard violation occurs, the purveyor shall:

     (i) Notify the department under WAC 246-290-480;

     (ii) Notify the consumers served by the system and the owner or operator of any consecutive system served in accordance with 40 CFR 141.201 through 208, and Part 7, Subpart A of this chapter;

     (iii) Determine the cause of the contamination; and

     (iv) Take action as directed by the department.

     (c) When a secondary standard violation occurs, the purveyor shall notify the department and take action as directed by the department.

     (d) The department may require additional sampling for confirmation of results.

     (2) Bacteriological.

     (a) When coliform bacteria are present in any sample and the sample is not invalidated under (d) of this subsection, the purveyor shall ensure the following actions are taken:

     (i) The sample is analyzed for fecal coliform or E. coli. When a sample with a coliform presence is not analyzed for E. coli or fecal coliforms, the sample shall be considered as having a fecal coliform presence for MCL compliance purposes;

     (ii) Repeat samples are collected in accordance with (b) of this subsection;

     (iii) The department is notified in accordance with WAC 246-290-480; and

     (iv) The cause of the coliform presence is determined and corrected.

     (b) Repeat samples.

     (i) The purveyor shall collect repeat samples in order to confirm the original sample results and to determine the cause of the coliform presence. Additional treatment, such as batch or shock chlorination, shall not be instituted prior to the collection of repeat samples unless prior authorization by the department is given. Following collection of repeat samples, and before the analytical results are known, there may be a need to provide interim precautionary treatment or other means to insure public health protection. The purveyor shall contact the department to determine the best interim approach in this situation.

     (ii) The purveyor shall collect and submit for analysis a set of repeat samples for every sample in which the presence of coliforms is detected. A set of repeat coliform samples consists of:

     (A) Four repeat samples for systems collecting one routine coliform sample each month; or

     (B) Three repeat samples for all systems collecting more than one routine coliform sample each month.

     (iii) The purveyor shall collect repeat sample sets according to Table 7;

     (iv) The purveyor shall collect one set of repeat samples for each sample with a coliform presence. All samples in a set of repeat samples shall be collected on the same day and submitted for analysis within twenty-four hours after notification by the laboratory of a coliform presence, or as directed by the department.

     (v) When repeat samples have coliform presence, the purveyor shall:

     (A) Contact the department and collect a minimum of one additional set of repeat samples as directed by the department; or

     (B) Collect one additional set of repeat samples for each sample where coliform presence was detected.

     (vi) The purveyor of a system providing water to consumers via a single service shall collect repeat samples from the same location as the sample with a coliform presence. The set of repeat samples shall be collected:

     (A) On the same collection date;

     (B) Over consecutive days with one sample collected each day until the required samples in the set of repeat samples are collected; or

     (C) As directed by the department.

     (vii) If a sample with a coliform presence was collected from the first two or last two active services, the purveyor shall monitor as directed by the department;

     (viii) The purveyor may change a previously submitted routine sample to a sample in a set of repeat samples when the purveyor:

     (A) Collects the sample within five adjacent service connections of the location from which the initial sample with a coliform presence was collected;

     (B) Collects the sample after the initial sample with a coliform presence was submitted for analysis;

     (C) Collects the sample on the same day as other samples in the set of repeat samples, except under (b)(iv) of this subsection; and

     (D) Requests and receives approval from the department for the change.

     (ix) The department may determine that sets of repeat samples specified under this subsection are not necessary during a month when a nonacute coliform MCL violation is determined for the system.
Table 7

REPEAT SAMPLE REQUIREMENTS


# OF ROUTINE

SAMPLES COLLECTED

EACH MONTH		 # OF SAMPLES

IN A SET OF

REPEAT

SAMPLES		 LOCATIONS FOR REPEAT

SAMPLES

(COLLECT AT LEAST ONE

SAMPLE PER SITE)
1

4 ♦ Site of previous sample with a coliform presence

♦ Within 5 active services upstream of site of sample with a coliform presence

♦ Within 5 active services downstream of site of sample with a coliform presence

♦ At any other active service or from a location most susceptible to contamination (i.e., well or reservoir)
more than 1



 3 ♦ Site of previous sample with a coliform presence

♦ Within 5 active services upstream of site of sample with a coliform presence

♦ Within 5 active services downstream of site of sample with a coliform presence


     (c) Monitoring frequency following a coliform presence. Systems having one or more coliform presence samples that were not invalidated during the previous month shall collect and submit for analysis the minimum number of samples shown in the last column of Table 2.

     (i) The purveyor may obtain a reduction in the monitoring frequency requirement when one or more samples with a coliform presence were collected during the previous month, if the purveyor proves to the satisfaction of the department;

     (A) The cause of the sample with a coliform presence; and

     (B) The problem is corrected before the end of the next month the system provides water to the public.

     (ii) If the monitoring frequency requirement is reduced, the purveyor shall collect and submit at least the minimum number of samples required when no samples with a coliform presence were collected during the previous month.

     (d) Invalid samples. Coliform samples may be determined to be invalid under any of the following conditions:

     (i) A certified laboratory determines that the sample results show:

     (A) Multiple tube technique cultures that are turbid without appropriate gas production;

     (B) Presence-absence technique cultures that are turbid in the absence of an acid reaction;

     (C) Occurrence of confluent growth patterns or growth of TNTC (too numerous to count) colonies without a surface sheen using a membrane filter analytic technique;

     (ii) The analyzing laboratory determines there is excess debris in the sample.

     (iii) The analyzing laboratory establishes that improper sample collection or analysis occurred;

     (iv) The department determines that a nondistribution system problem has occurred as indicated by:

     (A) All samples in the set of repeat samples collected at the same location, including households, as the original coliform presence sample also are coliform presence; and

     (B) All other samples from different locations (households, etc.) in the set of repeat samples are free of coliform.

     (v) The department determines a coliform presence result is due to a circumstance or condition that does not reflect water quality in the distribution system.

     (e) Follow-up action when an invalid sample is determined. The purveyor shall take the following action when a coliform sample is determined to be invalid:

     (i) Collect and submit for analysis an additional coliform sample from the same location as each invalid sample within twenty-four hours of notification of the invalid sample; or

     (ii) In the event that it is determined that the invalid sample resulted from circumstances or conditions not reflective of distribution system water quality, collect a set of samples in accordance with Table 7; and

     (iii) Collect and submit for analysis samples as directed by the department.

     (f) Invalidated samples shall not be included in determination of the sample collection requirement for compliance with this chapter.

     (3) Inorganic chemical and physical follow-up monitoring shall be conducted in accordance with the following:

     (a) For nonnitrate/nitrite primary inorganic chemicals, 40 CFR 141.23 (a)(4), 141.23 (b)(8), 141.23 (c)(7), 141.23 (c)(9), 141.23 (f)(1), 141.23(g), 141.23(m) and 141.23(n);

     (b) For nitrate, 40 CFR 141.23 (a)(4), 141.23 (d)(2), 141.23 (d)(3), 141.23 (f)(2), 141.23(g), 141.23(m), 141.23(n), and 141.23(o);

     (c) For nitrite, 40 CFR 141.23 (a)(4), 141.23 (e)(3), 141.23 (f)(2), and 141.23(g); or

     (d) The purveyor of any public water system providing service that has secondary inorganic MCL exceedances shall take follow-up action as required by the department. Follow-up action shall be commensurate with the degree of consumer acceptance of the water quality and their willingness to bear the costs of meeting the secondary standard. For new community water systems and new nontransient noncommunity water systems without active consumers, treatment for secondary contaminant MCL exceedances will be required.

     (4) Lead and copper follow-up monitoring shall be conducted in accordance with 40 CFR 141.85(d), 141.86 (d)(2), 141.86 (d)(3), 141.87(d) and 141.88(b) through 141.88(d).

     (5) Turbidity.

     Purveyors monitoring turbidity in accordance with Part 6 of this chapter shall provide follow-up under WAC 246-290-634.

     (6) Organic chemicals. Follow-up monitoring shall be conducted in accordance with the following:

     (a) For VOCs, 40 CFR 141.24 (f)(11) through 141.24 (f)(15), and 141.24 (f)(22); or

     (b) For SOCs, 40 CFR 141.24(b), 141.24(c) and 141.24 (h)(7) through 141.24 (h)(11), and 141.24 (h)(20).

     (7) Radionuclide follow-up monitoring shall be conducted under 40 CFR 141.26 (a)(2)(iv), 141.26 (a)(3)(ii) through (v), 141.26 (a)(4), 141.26 (b)(6), and 141.26 (c)(5).

     (8) The department shall determine the purveyor's follow-up action when a substance not included in this chapter is detected.



[Statutory Authority: RCW 70.119A.180 and 43.20.050. 08-03-061, § 246-290-320, filed 1/14/08, effective 2/14/08. Statutory Authority: RCW 43.20.050 and 70.119A.080. 04-04-056, § 246-290-320, filed 1/30/04, effective 3/1/04. Statutory Authority: RCW 43.20.050 (2) and (3) and70.119A.080 . 03-08-037, § 246-290-320, filed 3/27/03, effective 4/27/03. Statutory Authority: RCW 43.02.050 [43.20.050]. 99-07-021, § 246-290-320, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050. 94-14-001, § 246-290-320, filed 6/22/94, effective 7/23/94; 93-08-011 (Order 352B), § 246-290-320, filed 3/25/93, effective 4/25/93; 92-04-070 (Order 241B), § 246-290-320, filed 2/4/92, effective 3/6/92. Statutory Authority: Chapter 43.20 RCW. 91-07-031 (Order 150B), § 246-290-320, filed 3/15/91, effective 4/15/91. Statutory Authority: RCW 43.20.050. 91-02-051 (Order 124B), recodified as § 246-290-320, filed 12/27/90, effective 1/31/91. Statutory Authority: P.L. 99-339. 89-21-020 (Order 336), § 248-54-185, filed 10/10/89, effective 11/10/89. Statutory Authority: RCW 34.04.045. 88-05-057 (Order 307), § 248-54-185, filed 2/17/88. Statutory Authority: RCW 43.20.050. 83-19-002 (Order 266), § 248-54-185, filed 9/8/83.]