Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-11 - REGULATION NO. 11 - COLORADO PRIMARY DRINKING WATER REGULATIONS
Section 5 CCR 1002-11.21 - ORGANIC CHEMICALS RULE

Universal Citation: 5 CO Code Regs 1002-11 § 21

Current through Register Vol. 47, No. 17, September 10, 2024

11.21(1) Applicability and Definitions

(a) For all community and non-transient, non-community water systems, the supplier must comply with the requirements specified in this rule.

(b) "SYNTHETIC ORGANIC CHEMICALS" or "SOCs" mean all of the chemicals specified in Table 11.21-II.

11.21(2) MCL Requirements for Organic Chemicals

(a) MCL Requirements for VOCs

(i) The VOC MCLs and cited detection limits are as follows:

TABLE 11.21-I VOC MCLs AND DETECTION LIMITS
CAS No.	Chemical	MCL (mg/L)	Cited detection limit (mg/L)
75-01-4	Vinyl chloride	0.002	0.0005
71-43-2	Benzene	0.005	0.0005
56-23-5	Carbon tetrachloride	0.005	0.0005
107-06-2	1,2-Dichloroethane	0.005	0.0005
79-01-6	Trichloroethylene	0.005	0.0005
106-46-7	Para-Dichlorobenzene	0.075	0.0005
75-35-4	1,1-Dichloroethylene	0.007	0.0005
71-55-6	1,1,1-Trichloroethane	0.2	0.0005
156-59-2	cis-1,2 Dichloroethylene	0.07	0.0005
78-87-5	1,2-Dichloropropane	0.005	0.0005
100-41-4	Ethylbenzene	0.7	0.0005
108-90-7	Monochlorobenzene	0.1	0.0005
95-50-1	o-Dichlorobenzene	0.6	0.0005
100-42-5	Styrene	0.1	0.0005
127-18-4	Tetrachloroethylene	0.005	0.0005
108-88-3	Toluene	1	0.0005
156-60-5	Trans-1,2 Dichloroethylene	0.1	0.0005
1330-20-7	Xylenes (total)	10	0.0005
75-09-2	Dichloromethane (methylene chloride)	0.005	0.0005
120-82-1	1,2,4-Trichlorobenzene	0.07	0.0005
79-00-5	1,1,2-Trichloroethane	0.005	0.0005

(ii) The BATs for achieving compliance with the MCLs for VOCs are specified in 40 CFR 141.61(b).

(b) MCL Requirements for SOCs

(i) The SOC MCLs and cited detection limits are as follows:

TABLE 11.21-II SOC MCLs AND DETECTION LIMITS
CAS No.	Chemical	MCL (mg/L)	Cited detection limit (mg/L)
15972-60-8	Alachlor	0.002	0.0002
116-06-3	Aldicarb1	0.003	0.0005
1646-87-3	Aldicarb sulfoxide1	0.004	0.0005
1646-88-4	Aldicarb sulfone1	0.002	0.0008
1912-24-9	Atrazine	0.003	0.0001
1563-66-2	Carbofuran	0.04	0.0009
57-74-9	Chlordane	0.002	0.0002
96-12-8	Dibromochloropropane	0.0002	0.00002
94-75-7	2,4-D	0.07	0.0001
106-93-4	Ethylene dibromide	0.00005	0.00001
76-44-8	Heptachlor	0.0004	0.00004
1024-57-3	Heptachlor epoxide	0.0002	0.00002
58-89-9	Lindane	0.0002	0.00002
72-43-5	Methoxychlor	0.04	0.0001
1336-36-3	Polychlorinated biphenyls	0.0005	0.0001
87-86-5	Pentachlorophenol	0.001	0.00004
8001-35-2	Toxaphene	0.003	0.001
93-72-1	2,4,5-TP (Silvex)	0.05	0.0002
50-32-8	Benzopyrene	0.0002	0.00002
75-99-0	Dalapon	0.2	0.001
103-23-1	Di(2-ethylhexyl)adipate	0.4	0.0006
117-81-7	Di(2-ethylhexyl)phthalate	0.006	0.0006
88-85-7	Dinoseb	0.007	0.0002
85-00-7	Diquat	0.02	0.0004
145-73-3	Endothall	0.1	0.009
72-20-8	Endrin	0.002	0.00001
1071-53-6	Glyphosate	0.7	0.006
118-74-1	Hexachlorobenzene	0.001	0.0001
77-47-4	Hexachlorocyclopentadiene	0.05	0.0001
23135-22-0	Oxamyl (Vydate)	0.2	0.002
1918-02-1	Picloram	0.5	0.0001
122-34-9	Simazine	0.004	0.00007
1746-01-6	2,3,7,8-TCDD (Dioxin)	3 x 10-8	0.000000005

1 Aldicarb, aldicarb sulfoxide, and aldicarb sulfone are currently under "administrative stay" as a result of litigation. They are therefore treated as unregulated contaminants. The supplier is not required to sample for them or comply with their MCLs.

(ii) The BATs for achieving compliance with the MCLs for SOCs are specified in 40 CFR 141.61(b).

11.21(3) Sampling Requirements for Organic Chemicals

(a) General Sampling Requirements for Organic Chemicals

(i) To determine compliance with the MCLs for organic chemicals, the supplier must comply with the sampling specified in this section, 11.21(3).

(ii) The Department may:

(A) Require the supplier to sample more frequently than the minimum requirements specified in this section, 11.21(3).

(B) Require the supplier to collect a confirmation sample for any sample result.

(D) Specify when the supplier must sample during each monitoring period.

(iii) If the system draws water from more than one source and the sources are combined before distribution, the supplier must sample during periods of normal operating conditions.

(b) Sampling Requirements for VOCs

(i) To determine compliance with the MCLs for VOCs, the supplier must comply with the sampling requirements specified in this section, 11.21(3)(b).

(ii) For new systems, new sources, or reclassified systems that now meet the applicability of this rule, the supplier must sample for an initial four consecutive quarters at each entry point and demonstrate compliance with the MCLs no later than one year after beginning supplying water to the public or one year after being reclassified.

(A) For surface water systems, the supplier must sample for vinyl chloride as specified by the Department.

(B) For groundwater systems, the supplier must collect samples for vinyl chloride only as specified in 11.21(3)(b)(vi).

(iii) After completing initial sampling, if all sample results were less than (<) the cited detection limit at an entry point, the supplier must sample at a routine frequency at that entry point. For routine sampling, the supplier must collect one sample annually at that entry point.

(iv) For groundwater systems, if the supplier has collected at least three years of annual samples at an entry point and all sample results were less than or equal to ([LESS THAN EQUAL TO]) the cited detection limit, the Department may reduce the required sampling frequency at that entry point to once during each three-year compliance period.

(v) If any sample result is greater than (>) the cited detection limit, but less than or equal to ([LESS THAN EQUAL TO]) the MCL, the supplier must increase the sampling frequency to quarterly at each entry point where the detection occurred.

(A) The Department may allow the supplier to return to a routine sampling frequency if the Department determines that the sample results at that entry point are reliably and consistently below the MCL. To make that determination, the supplier must collect:

(I) For surface water systems, at least four quarters of samples at the entry point where the detection occurred.

(II) For groundwater systems, at least two quarters of samples at the entry point where the detection occurred.

(vi) For groundwater systems, if a sample result is greater than (>) the cited detection limit for one or more of the following chemicals, the supplier must sample quarterly for vinyl chloride at each entry point where the detection occurred:

(A) Trichloroethylene.

(B) Tetrachloroethylene.

(D) 1,1,1-trichloroethane.

(E) Cis-1,2-dichloroethylene.

(F) Trans-1,2-dichloroethylene.

(G) 1,1-dichloroethylene.

(vii) If the first sample result for vinyl chloride is less than or equal to ([LESS THAN EQUAL TO]) the cited detection limit, the Department may reduce the quarterly sampling frequency at that entry point to one sample during each three-year compliance period.

(viii) If any sample result is greater than (>) the MCL, the supplier must increase the sampling frequency to quarterly.

(A) The Department may allow the supplier to return to a routine sampling frequency if all of the following criteria are met:

(I) The supplier has collected four consecutive quarters of samples at that entry point after the exceedance that demonstrate that the system is in compliance.

(II) The Department determines that the sample results at that entry point are reliably and consistently below the MCL.

(ix) When returning to routine sampling, the supplier must collect samples during the quarter that previously resulted in the highest sample result.

(i) The supplier may apply to the Department for a VOC waiver if:

(A) After completing initial sampling, all sample results are less than (<) the cited detection limit for VOCs; or

(B) After three consecutive years of annual sampling following detection of a VOC, all sample results are less than (<) the cited detection limit.

(ii) If the Department grants a VOC waiver, the supplier is not required to sample at the frequencies specified in 11.21(3)(b).

(iii) The Department may grant a VOC waiver to the supplier if the supplier demonstrates that within the watershed or zone of influence no VOCs were used.

(iv) If VOCs have been used or VOC use is unknown, the Department shall consider all of the following factors to determine whether to grant a waiver:

(A) Previous sample results.

(B) How well the source is protected against contamination.

(I) For groundwater sources, the Department shall consider factors including depth of the well, the type of soil, and wellhead protection.

(II) For surface water sources, the Department shall consider watershed protection.

(I) Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities.

(D) The environmental persistence and transport of VOCs.

(E) The population supplied by the system and the proximity of a smaller system to a larger system.

(v) For groundwater systems, a VOC waiver is effective for six years.

(A) The supplier must update the vulnerability assessment during the effective period of the waiver.

(I) The Department shall reconfirm that the system is non-vulnerable based on the vulnerability assessment.

(a) If the Department does not reconfirm that the system is non-vulnerable no later than three years after the initial determination, the waiver is withdrawn.

(B) The supplier must collect one sample at each entry point while the waiver is effective.

(vi) For surface water systems, the Department shall specify how long a VOC waiver is effective.

(A) The Department shall determine if the system is non-vulnerable based on a vulnerability assessment completed during each compliance period.

(B) The supplier must collect one sample at each entry point at the Department-specified frequency while the waiver is effective.

(vii) For small groundwater systems, the Department may grant a waiver from the initial sampling requirements for 1,2,4-trichlorobenzene specified in 11.21(3)(b)(ii).

(d) Sampling Requirements for SOCs

(i) To determine compliance with the MCLs for SOCs, the supplier must comply with the sampling specified in this section, 11.21(3)(d).

(ii) For new systems, new sources, or reclassified systems that now meet the applicability of this rule, the supplier must collect an initial four consecutive quarters of samples at each entry point and demonstrate compliance with the MCL no later than one year after beginning supplying water to the public or one year after being reclassified.

(iii) After completing initial sampling, if all sample results for an SOC were less than (<) the cited detection limit at an entry point, the supplier must sample at a routine sampling frequency at that entry point. For routine sampling, the supplier must:

(A) For systems supplying greater than (>) 3,300 people, collect one sample in at least two different quarters in one calendar year during each three-year compliance period at that entry point.

(B) For systems supplying less than or equal to ([LESS THAN EQUAL TO]) 3,300 people, collect at least one sample during each three-year compliance period at that entry point.

(iv) If any sample result is greater than or equal to (>=) the cited detection limit for an SOC, but less than or equal to the ([LESS THAN EQUAL TO]) MCL, the supplier must increase the sampling frequency to quarterly for that SOC at each entry point where the detection occurred.

(A) If a sample result is greater than or equal to (>=) the cited detection limit for one or more of the following the supplier must increase the sampling frequency to quarterly for all of the following at that entry point:

(I) Aldicarb.

(II) Aldicarb sulfone.

(III) Aldicarb sulfoxide.

(B) If a sample result is greater than or equal to (>=) the cited detection limit for one or more of the following the supplier must increase the sampling frequency to quarterly for all of the following at that entry point:

(I) Heptachlor.

(II) Heptachlor epoxide.

(C) The Department may allow the supplier to reduce the sampling frequency to annually if the Department determines that the sample results at that entry point are reliably and consistently below the MCL. To make that determination, the supplier must collect:

(I) For surface water systems, at least four quarters of samples at the entry point where the detection occurred.

(II) For groundwater systems, at least two quarters of samples at the entry point where the detection occurred.

(v) If any sample result is greater than (>) the MCL, the supplier must increase the sampling frequency to quarterly.

(A) The Department may allow the supplier to reduce the sampling frequency to annually if all of the following criteria are met:

(I) The supplier has collected four consecutive quarters of samples at that entry point after the exceedance that demonstrate that the system is in compliance.

(II) The Department determines that the sample results at that entry point are reliably and consistently below the MCL.

(vi) When reducing to annual sampling, the supplier must sample during the quarter that previously resulted in the highest sample result.

(e) Sampling Waiver Requirements for SOCs

(i) The supplier may apply to the Department for a waiver from any or all of the SOCs.

(A) If an SOC is detected, the supplier must sample annually for three consecutive years and if all sample results are less than (<) the cited detection limit, the supplier may apply to the Department for a waiver.

(ii) If the Department grants the waiver, the supplier is not required to sample at the frequencies specified in 11.21(3)(d) for that SOC.

(iii) The Department may grant an SOC waiver to the supplier if the supplier demonstrates that within the watershed or zone of influence, that SOC was not used (including transport, storage, or disposal).

(iv) If an SOC has been used or the use is unknown, the Department shall consider all of the following factors in determining whether to grant a waiver:

(A) Previous sample results.

(B) How well the source is protected against contamination, factors may include the depth of the well, the type of soil, and the integrity of the well casing.

(II) Non-point sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.

(D) The environmental persistence and transport of pesticides or PCBs.

(E) Elevated nitrate levels at the source(s).

(F) Use of PCBs in equipment used in the production, storage, or distribution of water.

(v) The supplier must reapply for an SOC waiver each three-year compliance period.

11.21(4) Compliance Determination for Organic Chemicals

(a) If the supplier samples more frequently than annually, MCL compliance is based on the LRAA.

(i) If a confirmation sample is required, the original sample result will be replaced with the average of the original sample result and the confirmation sample result when calculating the LRAA.

(A) If the supplier fails to collect the confirmation sample, the original sample result will be used when calculating the LRAA.

(ii) If a sample result is less than (<) the cited detection limit, the sample result will be given a value of zero when calculating the LRAA.

(b) If the supplier samples annually or less frequently, MCL compliance is based on each individual sample result, unless a confirmation sample is required.

(i) If a confirmation sample is required, compliance will be based on by the average of the sample result and its confirmation sample result.

(A) If the supplier fails to collect the confirmation sample, the original sample result will be used to determine compliance.

(ii) If the sample result or average of any sample result and its confirmation sample result, if a confirmation sample is required, is greater than (>) the MCL, the supplier must increase the sampling frequency to quarterly as specified in 11.21(3)(b)(viii) and/or 11.21(3)(d)(v). This average, or sample result, will count as the first quarter result and compliance with the MCL will be based on an LRAA.

(c) The Department may determine compliance or initiate enforcement action based on sample results and other information gathered by Department-authorized representatives and agencies.

11.21(5) Acrylamide and Epichlorohydrin Certification

If acrylamide and epichlorohydrin are used in the drinking water system, the supplier must annually certify, in writing, to the Department, using a Department-approved third party or manufacturer's certification, that the combination of dose and monomer level is less than or equal to ([LESS THAN EQUAL TO]) the following levels:

(a) Acrylamide = 0.05% dosed at 1 ppm (or equivalent).

(b) Epichlorohydrin = 0.01% dosed at 20 ppm (or equivalent).

11.21(6) Violations for Organic Chemicals

(a) The following constitute organic chemical MCL violations:

(i) The LRAA at any entry point is greater than (>) the MCL for any organic chemical.

(ii) The LRAA, calculated before four consecutive quarters of samples have been collected at any entry point, is greater than (>) the MCL for any organic chemical regardless of the subsequent sample results.

(b) Failure to comply with the acrylamide and epichlorohydrin certification requirements as specified in 11.21(5) constitutes a treatment technique violation.

11.21(7) Response to Violations for Organic Chemicals

In the event of an organic chemical MCL violation or an acrylamide and epichlorohydrin treatment technique violation, the supplier must:

(a) Notify the Department no later than 48 hours after the violation occurs.

(b) Distribute Tier 2 public notice as specified in 11.33.

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Code of Colorado Regulations1000 - Department of Public Health and Environment1002 - Water Quality Control Commission (1002 Series)5 CCR 1002-11 - REGULATION NO. 11 - COLORADO PRIMARY DRINKING WATER REGULATIONSSection 5 CCR 1002-11.21 - ORGANIC CHEMICALS RULE

Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-11 - REGULATION NO. 11 - COLORADO PRIMARY DRINKING WATER REGULATIONS
Section 5 CCR 1002-11.21 - ORGANIC CHEMICALS RULE