PURPOSE: This rule establishes monitoring requirements for organic chemicals, volatile organic chemicals, and an inorganic chemical, which are unregulated in that they do not have maximum contaminant levels.

1. (1) This rule applies to community and nontransient noncommunity public water systems.
2. (2) Unless a waiver has been granted by the department, all public water systems shall conduct a one (1)-time round of sampling.
3. 1. Aldicarb;
4. 2. Aldicarb sulfoxide;
5. 3. Aldicarb sulfone;
6. 4. Aldrin;
7. 5. Butachlor;
8. 6. Carbaryl;
9. 7. Dicamba;
10. 8. Dieldrin;
11. 9. 3-Hydroxycarbofuran;
12. 10. Methomyl;
13. 11. Metolachlor;
14. 12. Metribuzin; and
15. 13. Propachlor;
16. 1. Sulfate.
17. 1. Bromobenzene;
18. 2. Bromodichloromethane;
19. 3. Bromoform;
20. 4. Bromomethane;
21. 5. Chlorodibromomethane;
22. 6. Chloroethane;
23. 7. Chloroform;
24. 8. Chloromethane;
25. 9. o-Chlorotoluene;
26. 10. p-Chlorotoluene;
27. 11. Dibromomethane;
28. 12. m-Dichlorobenzene;
29. 13. 1,1-Dichloroethane;
30. 14. 1,1-Dichloropropene;
31. 15. 1,3-Dichloropropane;
32. 16. 1,3-Dichloropropene;
33. 17. 2,2-Dichloropropane;
34. 18. 1,1,1,2-Tetrachloroethane;
35. 19. 1,1,2,2-Tetrachloroethane; and
36. 20. 1,2,3-Trichloropropane; and
37. 1. Bromochloromethane;
38. 2. n-Butylbenzene;
39. 3. Dichlorodifluoromethane;
40. 4. Fluorotrichloromethane;
41. 5. Hexachlorobutadiene;
42. 6. Isopropylbenzene;
43. 7. p-Isopropyltoluene;
44. 8. Naphthalene;
45. 9. n-Propylbenzene;
46. 10. sec-Butylbenzene;
47. 11. tert-Butylbenzene;
48. 12. 1,2,3-Trichlorobenzene;
49. 13. 1,2,4-Trimethylbenzene; and
50. 14. 1,3,5-Trimethylbenzene.
51. (4) All public water systems shall sample at points in the distribution system representative of each water source or at entry points to the distribution system. The sampling point will be after the application of treatment. The minimum number of samples is four consecutive quarterly samples per water source for the organic chemicals listed under subsection (2)(A) of this rule, and one (1) sample per water source for the inorganic chemical listed under subsection (2)(B) of this rule. Sampling must be completed no later than the end of the initial three (3)-year compliance period and results reported to the department. Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
52. (5) If the system draws water from more than one (1) source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions.

53. (6) A public water system may apply to the department for a waiver from the required sampling in section (3) for either organics or inorganics. All public water systems must conduct a one (1) time round of sampling.

    1. (A) A public water system may apply to the department for a use waiver for reduced monitoring from required organics sampling as required by 10 CSR 60-6.060(2) if previous use of the chemical can be ruled out or a public water system may apply to the department for a susceptibility waiver for reduced monitoring from required organics sampling contingent on the conduct of a thorough vulnerability assessment as required by 10 CSR 60- 6.060(3).
    2. (B) A public water system may apply to the department for susceptibility waivers for reduced monitoring from required inorganic sampling contingent on the conduct of a thorough vulnerability assessment as required by 10 CSR 60-6.060(3). Only data collected after January 1, 1990, will be considered in making this assessment.
    3. (C) A public water system serving fewer than one hundred fifty (150) service connections shall be treated as complying with the monitoring requirement if the owner or operator sends a letter to the department specifying that their system is available for sampling. This letter must be sent to the department no later than January 1, 1994.
54. (7) As determined by the department, confirmation samples may be required for either positive or negative results. AUTHORITY: section 640.100, RSMo 1994.* Original rule filed June 2, 1988, effective Aug. 31, 1988. Rescinded and readopted: Filed March 31, 1992, effective Dec. 3, 1992. Amended: Filed May 4, 1993, effective Jan. 13, 1994. Amended: Filed Feb. 1, 1996, effective Oct. 30, 1996. *Original authority: 640.100, RSMo 1939, amended 1978, 1981, 1982, 1988, 1989, 1992, 1993, 1995.