[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.24]
[Page 401-411]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
Subpart C_Monitoring and Analytical Requirements
Sec. 141.24 Organic chemicals, sampling and analytical requirements.
(a)-(d) [Reserved]
(e) Analyses for the contaminants in this section shall be conducted
using the following EPA methods or their equivalent as approved by EPA.
(1) The following documents are incorporated by reference. This
incorporation by reference was approved by the Director of the Federal
Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies
may be inspected at EPA's Drinking Water Docket, 1301 Constitution
Avenue, NW., EPA West, Room 3334, Washington, DC 20460 (Telephone: 202-
566-2426); or at the National Archives and Records Administration
(NARA). For information on the availability of this material at NARA,
call 202-741-6030, or go to: http://www.archives.gov/federal--register/
code--of--federal--regulations/ibr--locations.html. Method 508A and
515.1 are in Methods for the Determination of Organic Compounds in
Drinking Water, EPA/600/4-88-039, December 1988, Revised, July 1991.
Methods 547, 550 and 550.1 are in Methods for the Determination of
Organic Compounds in Drinking Water--Supplement I, EPA/600-4-90-020,
July 1990. Methods 548.1, 549.1, 552.1 and 555 are in Methods for the
Determination of Organic Compounds in Drinking Water--Supplement II,
EPA/600/R-92-129, August 1992. Methods 502.2, 504.1, 505, 506, 507, 508,
508.1, 515.2, 524.2 525.2, 531.1, 551.1 and 552.2 are in Methods for the
Determination of Organic Compounds in Drinking Water--Supplement III,
EPA/600/R-95-131, August 1995. Method 1613 is titled ``Tetra-through
Octa-Chlorinated Dioxins and Furans by Isotope-Dilution HRGC/HRMS,''
EPA/821-B-94-005, October 1994. These documents are available from the
National Technical Information Service, NTIS PB91-231480, PB91-146027,
PB92-207703, PB95-261616 and PB95-104774, U.S. Department of Commerce,
5285 Port Royal Road, Springfield, Virginia 22161. The toll free number
is: 800-553-6847. Method 6651 shall be followed in accordance with
Standard Methods for the Examination of Water and Wastewater, 18th
edition (1992), 19th edition (1995), or 20th edition (1998), American
Public Health Association (APHA); any of these three editions may be
used. Method 6610 shall be followed in accordance with Standard Methods
for the Examination of Water and Wastewater, (18th Edition Supplement)
(1994), or with the 19th edition (1995) or 20th edition (1998) of
Standard Methods for the Examination of Water and Wastewater;
[[Page 402]]
any of these publications may be used. The APHA documents are available
from APHA, 1015 Fifteenth Street NW., Washington, DC 20005. Other
required analytical test procedures germane to the conduct of these
analyses are contained in Technical Notes on Drinking Water Methods,
EPA/600/R-94-173, October 1994, NTIS PB95-104766. EPA Methods 515.3 and
549.2 are available from U.S. Environmental Protection Agency, National
Exposure Research Laboratory (NERL)-Cincinnati, 26 West Martin Luther
King Drive, Cincinnati, OH 45268. ASTM Method D 5317-93, 98 (Reapproved
2003) is available in the Annual Book of ASTM Standards, (1999), Vol.
11.02, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA
19428, any edition containing the cited version of the method may be
used. EPA Method 515.4, ``Determination of Chlorinated Acids in Drinking
Water by Liquid-Liquid Microextraction, Derivatization and Fast Gas
Chromatography with Electron Capture Detection,'' Revision 1.0, April
2000, EPA/815/B-00/001 and EPA Method 552.3, ``Determination of
Haloacetic Acids and Dalapon in Drinking Water by Liquid-Liquid
Microextraction, Derivatization, and Gas Chromatography with Electron
Capture Detection,'' Revision 1.0, July 2003, EPA 815-B-03-002, can be
accessed and downloaded directly online at http://www.epa.gov/safewater/
methods/sourcalt.html. Syngenta Method AG-625, ``Atrazine in Drinking
Water by Immunoassay,'' February 2001, is available from Syngenta Crop
Protection, Inc., 410 Swing Road, P.O. Box 18300, Greensboro, NC 27419.
Telephone: 336-632-6000. Method 531.2 ``Measurement of N-
methylcarbamoyloximes and N-methylcarbamates in Water by Direct Aqueous
Injection HPLC with Postcolumn Derivatization,'' Revision 1.0, September
2001, EPA 815-B-01-002, can be accessed and downloaded directly online
at http://www.epa.gov/ safewater/ methods/ sourcalt.html.
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Contaminant EPA method \1\ Standard methods ASTM Other
----------------------------------------------------------------------------------------------------------------
1. Benzene........................ 502.2, 524.2........
2. Carbon tetrachloride........... 502.2, 524.2, 551.1.
3. Chlorobenzene.................. 502.2, 524.2........
4. 1,2-Dichlorobenzene............ 502.2, 524.2........
5. 1,4-Dichlorobenzene............ 502.2, 524.2........
6. 1,2-Dichloroethane............. 502.2, 524.2........
7. cis-Dichloroethylene........... 502.2, 524.2........
8. trans-Dichloroethylene......... 502.2, 524.2........
9. Dichloromethane................ 502.2, 524.2........
10. 1,2-Dichloropropane........... 502.2, 524.2........
11. Ethylbenzene.................. 502.2, 524.2........
12. Styrene....................... 502.2, 524.2........
13. Tetrachloroethylene........... 502.2, 524.2, 551.1.
14. 1,1,1-Trichloroethane......... 502.2, 524.2, 551.1.
15. Trichloroethylene............. 502.2, 524.2, 551.1.
16. Toluene....................... 502.2, 524.2........
17. 1,2,4-Trichlorobenzene........ 502.2, 524.2........
18. 1,1-Dichloroethylene.......... 502.2, 524.2........
19. 1,1,2-Trichloroethane......... 502.2, 524.2, 551.1.
20. Vinyl chloride................ 502.2, 524.2........
21. Xylenes (total)............... 502.2, 524.2........
22. 2,3,7,8-TCDD (dioxin)......... 1613................
23. 2,4-D \4\ (as acids, salts, 515.2, 555, 515.1, .................... D5317-93, 98
and esters). 515.3, 515.4. (Reapproved
2003).
24. 2,4,5-TP \4\ (Silvex)......... 515.2, 555, 515.1, .................... D5317-93, 98
515.3, 515.4. (Reapproved
2003).
25. Alachlor \2\.................. 507, 525.2, 508.1,
505, 551.1.
26. Atrazine \2\.................. 507, 525.2, 508.1, .................... ............... Syngenta \5\ AG-
505, 551.1. 625
27. Benzo(a)pyrene................ 525.2, 550, 550.1...
28. Carbofuran.................... 531.1, 531.2........ 6610................
29. Chlordane..................... 508, 525.2, 508.1,
505.
30. Dalapon....................... 552.1 515.1, 552.2,
515.3, 515.4, 552.3.
[[Page 403]]
31. Di(2-ethylhexyl)adipate....... 506, 525.2..........
32. Di(2-ethylhexyl)phthalate..... 506, 525.2..........
33. Dibromochloropropane (DBCP)... 504.1, 551.1........
34. Dinoseb \4\................... 515.2, 555, 515.1,
515.3, 515.4.
35. Diquat........................ 549.2...............
36. Endothall..................... 548.1...............
37. Endrin........................ 508, 525.2, 508.1,
505, 551.1.
38. Ethylene dibromide (EDB)...... 504.1, 551.1........
39. Glyphosate.................... 547................. 6651................
40. Heptachlor.................... 508, 525.2, 508.1,
505, 551.1.
41. Heptachlor Epoxide............ 508, 525.2, 508.1,
505, 551.1.
42. Hexachlorobenzene............. 508, 525.2, 508.1,
505, 551.1.
43. Hexachlorocyclopentadiene..... 508, 525.2, 508.1,
505, 551.1.
44. Lindane....................... 508, 525.2, 508.1,
505, 551.1.
45. Methoxychlor.................. 508, 525.2, 508.1,
505, 551.1.
46. Oxamyl........................ 531.1, 531.2........ 6610................
47. PCBs \3\ (as 508A................
decachlorobiphenyl).
48. PCBs \3\ (as Aroclors)........ 508.1, 508, 525.2,
505.
49. Pentachlorophenol............. 515.2, 525.2, 555, .................... D5317-93, 98
515.1, 515.3, 515.4. (Reapproved
2003).
50. Picloram \4\.................. 515.2, 555, 515.1, .................... D5317-93, 98
515.3, 515.4. (Reapproved
2003).
51. Simazine \2\.................. 507, 525.2, 508.1,
505, 551.1.
52. Toxaphene..................... 508, 508.1, 525.2,
505.
53. Total Trihalomethanes......... 502.2, 524.2, 551.1.
----------------------------------------------------------------------------------------------------------------
\1\ For previously approved EPA methods which remain available for compliance monitoring until June 1, 2001, see
paragraph (e)(2) of this section.
\2\ Substitution of the detector specified in Method 505, 507, 508 or 508.1 for the purpose of achieving lower
detection limits is allowed as follows. Either an electron capture or nitrogen phosphorous detector may be
used provided all regulatory requirements and quality control criteria are met.
\3\ PCBs are qualitatively identified as Aroclors and measured for compliance purposes as decachlorobiphenyl.
Users of Method 505 may have more difficulty in achieving the required detection limits than users of Methods
508.1, 525.2 or 508.
\4\ Accurate determination of the chlorinated esters requires hydrolysis of the sample as described in EPA
Methods 515.1, 515.2, 515.3, 515.4 and 555 and ASTM Method D5317-93.
\5\ This method may not be used for the analysis of atrazine in any system where chlorine dioxide is used for
drinking water treatment. In samples from all other systems, any result for atrazine generated by Method AG-
625 that is greater than one-half the maximum contaminant level (MCL) (in other words, greater than 0.0015mg/L
or 1.5 [mu]g/L) must be confirmed using another approved method for this contaminant and should use additional
volume of the original sample collected for compliance monitoring. In instances where a result from Method AG-
625 triggers such confirmatory testing, the confirmatory result is to be used to determine compliance.
(2) The following EPA methods will remain available for compliance
monitoring until June 1, 2001. The following documents are incorporated
by reference. This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and
1 CFR Part 51. Copies may be inspected at EPA's Drinking Water Docket,
401 M St., SW., Washington, DC 20460; or at the National Archives and
Records Administration (NARA). For information on the availability of
this material at NARA, call 202-741-6030, or go to: http://
www.archives.gov/federal--register/code--of--federal--regulations/ibr--
locations.html. EPA methods 502.2 Rev. 2.0, 505 Rev. 2.0, 507 Rev. 2.0,
508 Rev. 3.0, 531.1 Rev. 3.0 are in ``Methods for the Determination of
Organic Compounds in Drinking Water'', December 1988, revised July 1991;
methods 506 and 551 are in ``Methods for the Determination of Organic
Compounds in Drinking Water--Supplement I'', July 1990; methods 515.2
Rev. 1.0 and 524.2 Rev. 4.0 are in ``Methods for the Determination of
Organic Compounds in Drinking Water--Supplement II,'' August 1992; and
methods 504.1 Rev. 1.0, 508.1 Rev. 1.0, 525.2 Rev.1.0 are available from
US EPA NERL, Cincinnati, OH 45268
(f) Beginning with the initial compliance period, analysis of the
contaminants listed in Sec. 141.61(a) (1) through (21) for the purpose
of determining compliance with the maximum contaminant level shall be
conducted as follows:
[[Page 404]]
(1) Groundwater systems shall take a minimum of one sample at every
entry point to the distribution system which is representative of each
well after treatment (hereafter called a sampling point). Each sample
must be taken at the same sampling point unless conditions make another
sampling point more representative of each source, treatment plant, or
within the distribution system.
(2) Surface water systems (or combined surface/ground) shall take a
minimum of one sample at points in the distribution system that are
representative of each source or at each entry point to the distribution
system after treatment (hereafter called a sampling point). Each sample
must be taken at the same sampling point unless conditions make another
sampling point more representative of each source, treatment plant, or
within the distribution system.
(3) If the system draws water from more than one 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 (i.e., when water representative of all sources is
being used).
(4) Each community and non-transient non-community water system
shall take four consecutive quarterly samples for each contaminant
listed in Sec. 141.61(a) (2) through (21) during each compliance
period, beginning in the initial compliance period.
(5) If the initial monitoring for contaminants listed in Sec.
141.61(a) (1) through (8) and the monitoring for the contaminants listed
in Sec. 141.61(a) (9) through (21) as allowed in paragraph (f)(18) has
been completed by December 31, 1992, and the system did not detect any
contaminant listed in Sec. 141.61(a) (1) through (21), then each ground
and surface water system shall take one sample annually beginning with
the initial compliance period.
(6) After a minimum of three years of annual sampling, the State may
allow groundwater systems with no previous detection of any contaiminant
listed in Sec. 141.61(a) to take one sample during each compliance
period.
(7) Each community and non-transient non-community ground water
system which does not detect a contaminant listed in Sec. 141.61(a) (1)
through (21) may apply to the State for a waiver from the requirements
of paragraphs (f)(5) and (f)(6) of this section after completing the
initial monitoring. (For purposes of this section, detection is defined
as =0.0005 mg/l.) A waiver shall be effective for no more
than six years (two compliance periods). States may also issue waivers
to small systems for the initial round of monitoring for 1,2,4-
trichlorobenzene.
(8) A State may grant a waiver after evaluating the following
factor(s):
(i) Knowledge of previous use (including transport, storage, or
disposal) of the contaminant within the watershed or zone of influence
of the system. If a determination by the State reveals no previous use
of the contaminant within the watershed or zone of influence, a waiver
may be granted.
(ii) If previous use of the contaminant is unknown or it has been
used previously, then the following factors shall be used to determine
whether a waiver is granted.
(A) Previous analytical results.
(B) The proximity of the system to a potential point or non-point
source of contamination. 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.
(C) The environmental persistence and transport of the contaminants.
(D) The number of persons served by the public water system and the
proximity of a smaller system to a larger system.
(E) How well the water source is protected against contamination,
such as whether it is a surface or groundwater system. Groundwater
systems must consider factors such as depth of the well, the type of
soil, and wellhead protection. Surface water systems must consider
watershed protection.
(9) As a condition of the waiver a groundwater system must take one
sample at each sampling point during the time the waiver is effective
(i.e., one sample during two compliance periods or six years) and update
its vulnerability assessment considering the
[[Page 405]]
factors listed in paragraph (f)(8) of this section. Based on this
vulnerability assessment the State must reconfirm that the system is
non-vulnerable. If the State does not make this reconfirmation within
three years of the initial determination, then the waiver is invalidated
and the system is required to sample annually as specified in paragraph
(5) of this section.
(10) Each community and non-transient non-community surface water
system which does not detect a contaminant listed in Sec. 141.61(a) (1)
through (21) may apply to the State for a waiver from the requirements
of (f)(5) of this section after completing the initial monitoring.
Composite samples from a maximum of five sampling points are allowed,
provided that the detection limit of the method used for analysis is
less than one-fifth of the MCL. Systems meeting this criterion must be
determined by the State to be non-vulnerable based on a vulnerability
assessment during each compliance period. Each system receiving a waiver
shall sample at the frequency specified by the State (if any).
(11) If a contaminant listed in Sec. 141.61(a) (2) through (21) is
detected at a level exceeding 0.0005 mg/l in any sample, then:
(i) The system must monitor quarterly at each sampling point which
resulted in a detection.
(ii) The State may decrease the quarterly monitoring requirement
speci fied in paragraph (f)(11)(i) of this section provided it has
determined that the system is reliably and consistently below the
maximum contaminant level. In no case shall the State make this
determination unless a groundwater system takes a minimum of two
quarterly samples and a surface water system takes a minimum of four
quarterly samples.
(iii) If the State determines that the system is reliably and
consistently below the MCL, the State may allow the system to monitor
annually. Systems which monitor annually must monitor during the
quarter(s) which previously yielded the highest analytical result.
(iv) Systems which have three consecutive annual samples with no
detection of a contaminant may apply to the State for a waiver as
specified in paragraph (f)(7) of this section.
(v) Groundwater systems which have detected one or more of the
following two-carbon organic compounds: trichloroethylene,
tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, cis-1,2-
dichloroethylene, trans-1,2-dichloroethylene, or 1,1-dichloroethylene
shall monitor quarterly for vinyl chloride. A vinyl chloride sample
shall be taken at each sampling point at which one or more of the two-
carbon organic compounds was detected. If the results of the first
analysis do not detect vinyl chloride, the State may reduce the
quarterly monitoring frequency of vinyl chloride monitoring to one
sample during each compliance period. Surface water systems are required
to monitor for vinyl chloride as specified by the State.
(12) Systems which violate the requirements of Sec. 141.61(a) (1)
through (21), as determined by paragraph (f)(15) of this section, must
monitor quarterly. After a minimum of four consecutive quarterly samples
which show the system is in compliance as specified in paragraph (f)(15)
of this section the system and the State determines that the system is
reliably and consistently below the maximum contaminant level, the
system may monitor at the frequency and times specified in paragraph
(f)(11)(iii) of this section.
(13) The State may require a confirmation sample for positive or
negative results. If a confirmation sample is required by the State, the
result must be averaged with the first sampling result and the average
is used for the compliance determination as specified by paragraph
(f)(15). States have discretion to delete results of obvious sampling
errors from this calculation.
(14) The State may reduce the total number of samples a system must
analyze by allowing the use of compositing. Composite samples from a
maximum of five sampling points are allowed, provided that the detection
limit of the method used for analysis is less than one-fifth of the MCL.
Compositing of samples must be done in the laboratory and analyzed
within 14 days of sample collection.
(i) If the concentration in the composite sample is greater than or
equal
[[Page 406]]
to 0.0005 mg/l for any contaminant listed in Sec. 141.61(a), then a
follow-up sample must be taken within 14 days at each sampling point
included in the composite, and be analyzed for that contaminant.
(ii) If duplicates of the original sample taken from each sampling
point used in the composite sample are available, the system may use
these instead of resampling. The duplicates must be analyzed and the
results reported to the State within 14 days after completing analysis
of the composite sample, provided the holding time of the sample is not
exceeded.
(iii) If the population served by the system is 3,300
persons, then compositing may only be permitted by the State at sampling
points within a single system. In systems serving <= 3,300 persons, the
State may permit compositing among different systems provided the 5-
sample limit is maintained.
(iv) Compositing samples prior to GC analysis.
(A) Add 5 ml or equal larger amounts of each sample (up to 5 samples
are allowed) to a 25 ml glass syringe. Special precautions must be made
to maintain zero headspace in the syringe.
(B) The samples must be cooled at 4 [deg]C during this step to
minimize volatilization losses.
(C) Mix well and draw out a 5-ml aliquot for analysis.
(D) Follow sample introduction, purging, and desorption steps
described in the method.
(E) If less than five samples are used for compositing, a
proportionately small syringe may be used.
(v) Compositing samples prior to GC/MS analysis.
(A) Inject 5-ml or equal larger amounts of each aqueous sample (up
to 5 samples are allowed) into a 25-ml purging device using the sample
introduction technique described in the method.
(B) The total volume of the sample in the purging device must be 25
ml.
(C) Purge and desorb as described in the method.
(15) Compliance with Sec. 141.61(a) (1) through (21) shall be
determined based on the analytical results obtained at each sampling
point. If one sampling point is in violation of an MCL, the system is in
violation of the MCL.
(i) For systems monitoring more than once per year, compliance with
the MCL is determined by a running annual average at each sampling
point.
(ii) Systems monitoring annually or less frequently whose sample
result exceeds the MCL must begin quarterly sampling. The system will
not be considered in violation of the MCL until it has completed one
year of quarterly sampling.
(iii) If any sample result will cause the running annual average to
exceed the MCL at any sampling point, the system is out of compliance
with the MCL immediately.
(iv) If a system fails to collect the required number of samples,
compliance will be based on the total number of samples collected.
(v) If a sample result is less than the detection limit, zero will
be used to calculate the annual average.
(16) [Reserved]
(17) Analysis under this section shall only be conducted by
laboratories that are certified by EPA or the State according to the
following conditions (laboratories may conduct sample analysis under
provisional certification until January 1, 1996):
(i) To receive certification to conduct analyses for the
contaminants in Sec. 141.61(a) (2) through (21) the laboratory must:
(A) Analyze Performance Evaluation (PE) samples provided by EPA, the
State, or by a third party (with the approval of the State or EPA) at
least once a year by each method for which the laboratory desires
certification.
(B) Achieve the quantitative acceptance limits under paragraphs
(f)(17)(i)(C) and (D) of this section for at least 80 percent of the
regulated organic contaminants included in the PE sample.
(C) Achieve quantitative results on the analyses performed under
paragraph (f)(17)(i)(A) of this section that are within 20% of the actual amount of the substances in the
Performance Evaluation sample when the actual amount is greater than or
equal to 0.010 mg/l.
[[Page 407]]
(D) Achieve quantitative results on the analyses performed under
paragraph (f)(17)(i)(A) of this section that are within 40 percent of the actual amount of the substances in the
Performance Evaluation sample when the actual amount is less than 0.010
mg/l.
(E) Achieve a method detection limit of 0.0005 mg/l, according to
the procedures in appendix B of part 136.
(ii) To receive certification to conduct analyses for vinyl
chloride, the laboratory must:
(A) Analyze Performance Evaluation (PE) samples provided by EPA, the
State, or by a third party (with the approval of the State or EPA) at
least once a year by each method for which the laboratory desires
certification.
(B) Achieve quantitative results on the analyses performed under
paragraph (f)(17)(ii)(A) of this section that are within 40 percent of the actual amount of vinyl chloride in the
Performance Evaluation sample.
(C) Achieve a method detection limit of 0.0005 mg/l, according to
the procedures in appendix B of part 136.
(D) Obtain certification for the contaminants listed in Sec.
141.61(a)(2) through (21).
(18) States may allow the use of monitoring data collected after
January 1, 1988, required under section 1445 of the Act for purposes of
initial monitoring compliance. If the data are generally consistent with
the other requirements of this section, the State may use these data
(i.e., a single sample rather than four quarterly samples) to satisfy
the initial monitoring requirement of paragraph (f)(4) of this section.
Systems which use grandfathered samples and did not detect any
contaminant listed Sec. 141.61(a)(2) through (21) shall begin
monitoring annually in accordance with paragraph (f)(5) of this section
beginning with the initial compliance period.
(19) States may increase required monitoring where necessary to
detect variations within the system.
(20) Each certified laboratory must determine the method detection
limit (MDL), as defined in appendix B to part 136, at which it is
capable of detecting VOCs. The acceptable MDL is 0.0005 mg/l. This
concentration is the detection concentration for purposes of this
section.
(21) Each public water system shall monitor at the time designated
by the State within each compliance period.
(22) All new systems or systems that use a new source of water that
begin operation after January 22, 2004 must demonstrate compliance with
the MCL within a period of time specified by the State. The system must
also comply with the initial sampling frequencies specified by the State
to ensure a system can demonstrate compliance with the MCL. Routine and
increased monitoring frequencies shall be conducted in accordance with
the requirements in this section.
(g) [Reserved]
(h) Analysis of the contaminants listed in Sec. 141.61(c) for the
purposes of determining compliance with the maximum contaminant level
shall be conducted as follows, with the exception that no monitoring is
required for aldicarb, aldicarb sulfoxide or aldicarb sulfone:
(1) Groundwater systems shall take a minimum of one sample at every
entry point to the distribution system which is representative of each
well after treatment (hereafter called a sampling point). Each sample
must be taken at the same sampling point unless conditions make another
sampling point more representative of each source or treatment plant.
(2) Surface water systems shall take a minimum of one sample at
points in the distribution system that are representative of each source
or at each entry point to the distribution system after treatment
(hereafter called a sampling point). Each sample must be taken at the
same sampling point unless conditions make another sampling point more
representative of each source or treatment plant.
Note: For purposes of this paragraph, surface water systems include
systems with a combination of surface and ground sources.
(3) If the system draws water from more than one 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 (i.e., when water representative of all sources is
being used).
[[Page 408]]
(4) Monitoring frequency:
(i) Each community and non-transient non-community water system
shall take four consecutive quarterly samples for each contaminant
listed in Sec. 141.61(c) during each compliance period beginning with
the initial compliance period.
(ii) Systems serving more than 3,300 persons which do not detect a
contaminant in the initial compliance period may reduce the sampling
frequency to a minimum of two quarterly samples in one year during each
repeat compliance period.
(iii) Systems serving less than or equal to 3,300 persons which do
not detect a contaminant in the initial compliance period may reduce the
sampling frequency to a minimum of one sample during each repeat
compliance period.
(5) Each community and non-transient water system may apply to the
State for a waiver from the requirement of paragraph (h)(4) of this
section. A system must reapply for a waiver for each compliance period.
(6) A State may grant a waiver after evaluating the following
factor(s): Knowledge of previous use (including transport, storage, or
disposal) of the contaminant within the watershed or zone of influence
of the system. If a determination by the State reveals no previous use
of the contaminant within the watershed or zone of influence, a waiver
may be granted. If previous use of the contaminant is unknown or it has
been used previously, then the following factors shall be used to
determine whether a waiver is granted.
(i) Previous analytical results.
(ii) The proximity of the system to a potential point or non-point
source of contamination. 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. 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.
(iii) The environmental persistence and transport of the pesticide
or PCBs.
(iv) How well the water source is protected against contamination
due to such factors as depth of the well and the type of soil and the
integrity of the well casing.
(v) Elevated nitrate levels at the water supply source.
(vi) Use of PCBs in equipment used in the production, storage, or
distribution of water (i.e., PCBs used in pumps, transformers, etc.).
(7) If an organic contaminant listed in Sec. 141.61(c) is detected
(as defined by paragraph (h)(18) of this section) in any sample, then:
(i) Each system must monitor quarterly at each sampling point which
resulted in a detection.
(ii) The State may decrease the quarterly monitoring requirement
specified in paragraph (h)(7)(i) of this section provided it has
determined that the system is reliably and consistently below the
maximum contaminant level. In no case shall the State make this
determination unless a groundwater system takes a minimum of two
quarterly samples and a surface water system takes a minimum of four
quarterly samples.
(iii) After the State determines the system is reliably and
consistently below the maximum contaminant level the State may allow the
system to monitor annually. Systems which monitor annually must monitor
during the quarter that previously yielded the highest analytical
result.
(iv) Systems which have 3 consecutive annual samples with no
detection of a contaminant may apply to the State for a waiver as
specified in paragraph (h)(6) of this section.
(v) If the monitoring results in detection of one or more of certain
related contaminants (heptachlor and heptachlor epoxide), then
subsequent monitoring shall analyze for all related contaminants.
(8) Systems which violate the requirements of Sec. 141.61(c) as
determined by paragraph (h)(11) of this section must monitor quarterly.
After a minimum of four quarterly samples show the system is in
compliance and the State determines the system is reliably and
consistently below the MCL, as specified in paragraph (h)(11) of this
section, the system shall monitor at
[[Page 409]]
the frequency specified in paragraph (h)(7)(iii) of this section.
(9) The State may require a confirmation sample for positive or
negative results. If a confirmation sample is required by the State, the
result must be averaged with the first sampling result and the average
used for the compliance determination as specified by paragraph (h)(11)
of this section. States have discretion to delete results of obvious
sampling errors from this calculation.
(10) The State may reduce the total number of samples a system must
analyze by allowing the use of compositing. Composite samples from a
maximum of five sampling points are allowed, provided that the detection
limit of the method used for analysis is less than one-fifth of the MCL.
Compositing of samples must be done in the laboratory and analyzed
within 14 days of sample collection.
(i) If the concentration in the composite sample detects one or more
contaminants listed in Sec. 141.61(c), then a follow-up sample must be
taken within 14 days at each sampling point included in the composite,
and be analyzed for that contaminant.
(ii) If duplicates of the original sample taken from each sampling
point used in the composite sample are available, the system may use
these instead of resampling. The duplicates must be analyzed and the
results reported to the State within 14 days after completion of the
composite analysis or before the holding time for the initial sample is
exceeded whichever is sooner.
(iii) If the population served by the system is 3,300
persons, then compositing may only be permitted by the State at sampling
points within a single system. In systems serving <= 3,300 persons, the
State may permit compositing among different systems provided the 5-
sample limit is maintained.
(11) Compliance with Sec. 141.61(c) shall be determined based on
the analytical results obtained at each sampling point. If one sampling
point is in violation of an MCL, the system is in violation of the MCL.
(i) For systems monitoring more than once per year, compliance with
the MCL is determined by a running annual average at each sampling
point.
(ii) Systems monitoring annually or less frequently whose sample
result exceeds the regulatory detection level as defined by paragraph
(h)(18) of this section must begin quarterly sampling. The system will
not be considered in violation of the MCL until it has completed one
year of quarterly sampling.
(iii) If any sample result will cause the running annual average to
exceed the MCL at any sampling point, the system is out of compliance
with the MCL immediately.
(iv) If a system fails to collect the required number of samples,
compliance will be based on the total number of samples collected.
(v) If a sample result is less than the detection limit, zero will
be used to calculate the annual average.
(12) [Reserved]
(13) Analysis for PCBs shall be conducted as follows using the
methods in paragraph (e) of this section:
(i) Each system which monitors for PCBs shall analyze each sample
using either Method 508.1, 525.2, 508 or 505. Users of Method 505 may
have more difficulty in achieving the required Aroclor detection limits
than users of Methods 508.1, 525.2 or 508.
(ii) If PCBs (as one of seven Aroclors) are detected (as designated
in this paragraph) in any sample analyzed using Method 505 or 508, the
system shall reanalyze the sample using Method 508A to quantitate PCBs
(as decachlorobiphenyl).
------------------------------------------------------------------------
Detection limit
Aroclor (mg/l)
------------------------------------------------------------------------
1016................................................. 0.00008
1221................................................. 0.02
1232................................................. 0.0005
1242................................................. 0.0003
1248................................................. 0.0001
1254................................................. 0.0001
1260................................................. 0.0002
------------------------------------------------------------------------
(iii) Compliance with the PCB MCL shall be determined based upon the
quantitative results of analyses using Method 508A.
(14) If monitoring data collected after January 1, 1990, are
generally consistent with the requirements of Sec. 141.24(h), then the
State may allow systems to use that data to satisfy the monitoring
requirement for the initial
[[Page 410]]
compliance period beginning January 1, 1993.
(15) The State may increase the required monitoring frequency, where
necessary, to detect variations within the system (e.g., fluctuations in
concentration due to seasonal use, changes in water source).
(16) The State has the authority to determine compliance or initiate
enforcement action based upon analytical results and other information
compiled by their sanctioned representatives and agencies.
(17) Each public water system shall monitor at the time designated
by the State within each compliance period.
(18) Detection as used in this paragraph shall be defined as greater
than or equal to the following concentrations for each contaminant.
------------------------------------------------------------------------
Detection
Contaminant limit (mg/
l)
------------------------------------------------------------------------
Alachlor................................................... .0002
Aldicarb................................................... .0005
Aldicarb sulfoxide......................................... .0005
Aldicarb sulfone........................................... .0008
Atrazine................................................... .0001
Benzo[a]pyrene............................................. .00002
Carbofuran................................................. .0009
Chlordane.................................................. .0002
Dalapon.................................................... .001
1,2-Dibromo-3-chloropropane (DBCP)......................... .00002
Di (2-ethylhexyl) adipate.................................. .0006
Di (2-ethylhexyl) phthalate................................ .0006
Dinoseb.................................................... .0002
Diquat..................................................... .0004
2,4-D...................................................... .0001
Endothall.................................................. .009
Endrin..................................................... .00001
Ethylene dibromide (EDB)................................... .00001
Glyphosate................................................. .006
Heptachlor................................................. .00004
Heptachlor epoxide......................................... .00002
Hexachlorobenzene.......................................... .0001
Hexachlorocyclopentadiene.................................. .0001
Lindane.................................................... .00002
Methoxychlor............................................... .0001
Oxamyl..................................................... .002
Picloram................................................... .0001
Polychlorinated biphenyls (PCBs) (as decachlorobiphenyl)... .0001
Pentachlorophenol.......................................... .00004
Simazine................................................... .00007
Toxaphene.................................................. .001
2,3,7,8-TCDD (Dioxin)...................................... .000000005
2,4,5-TP (Silvex).......................................... .0002
------------------------------------------------------------------------
(19) Anaylsis under this section shall only be conducted by
laboratories that have received certification by EPA or the State and
have met the following conditions:
(i) To receive certification to conduct analyses for the
contaminants in Sec. 141.61(c) the laboratory must:
(A) Analyze Performance Evaluation (PE) samples provided by EPA, the
State, or by a third party (with the approval of the State or EPA) at
least once a year by each method for which the laboratory desires
certification.
(B) For each contaminant that has been included in the PE sample
achieve quantitative results on the analyses that are within the
following acceptance limits:
------------------------------------------------------------------------
Contaminant Acceptance limits (percent)
------------------------------------------------------------------------
DBCP...................................... 40
EDB....................................... 40.
Alachlor.................................. 45.
Atrazine.................................. 45.
Benzo[a]pyrene............................ 2 standard deviations.
Carbofuran................................ 45.
Chlordane................................. 45.
Dalapon................................... 2 standard deviations.
Di(2-ethylhexyl)adipate................... 2 standard deviations.
Di(2-ethylhexyl)phthalate................. 2 standard deviations.
Dinoseb................................... 2 standard deviations.
Diquat.................................... 2 standard deviations.
Endothall................................. 2 standard deviations.
Endrin.................................... 30.
Glyphosate................................ 2 standard deviations.
Heptachlor................................ 45.
Heptachlor epoxide........................ 45.
Hexachlorobenzene......................... 2 standard deviations.
Hexachloro- cyclopentadiene 2 standard deviations.
Lindane................................... 45.
Methoxychlor.............................. 45.
Oxamyl.................................... 2 standard deviations.
PCBs (as Decachlorobiphenyl) 0-200.
Picloram.................................. 2 standard deviations.
Simazine.................................. 2 standard deviations.
Toxaphene................................. 45.
Aldicarb.................................. 2 standard deviations.
Aldicarb sulfoxide........................ 2 standard deviations.
Aldicarb sulfone.......................... 2 standard deviations.
Pentachlorophenol......................... 50.
2,3,7,8-TCDD (Dioxin)..................... 2 standard deviations.
2,4-D..................................... 50.
2,4,5-TP (Silvex)......................... 50.
------------------------------------------------------------------------
(ii) [Reserved]
(20) All new systems or systems that use a new source of water that
begin operation after January 22, 2004 must demonstrate compliance with
the MCL within a period of time specified by the State. The system must
also comply with the initial sampling frequencies specified by the State
to ensure a system can demonstrate compliance with the MCL. Routine and
increased monitoring frequencies shall be conducted in accordance with
the requirements in this section.
(Approved by the Office of Management and Budget under control number
2040-0090)
[40 FR 59570, Dec. 24, 1975]
[[Page 411]]
Editorial Note: For Federal Register citations affecting Sec.
141.24, see the List of CFR Sections Affected, which appears in the
Finding Aids section of the printed volume and on GPO Access.