[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.2]
[Page 345-351]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
Subpart A_General
Sec. 141.2 Definitions.
As used in this part, the term:
Act means the Public Health Service Act, as amended by the Safe
Drinking Water Act, Public Law 93-523.
Action level, is the concentration of lead or copper in water
specified in
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Sec. 141.80(c) which determines, in some cases, the treatment
requirements contained in subpart I of this part that a water system is
required to complete.
Best available technology or BAT means the best technology,
treatment techniques, or other means which the Administrator finds,
after examination for efficacy under field conditions and not solely
under laboratory conditions, are available (taking cost into
consideration). For the purposes of setting MCLs for synthetic organic
chemicals, any BAT must be at least as effective as granular activated
carbon.
Coagulation means a process using coagulant chemicals and mixing by
which colloidal and suspended materials are destabilized and
agglomerated into flocs.
Community water system means a public water system which serves at
least 15 service connections used by year-round residents or regularly
serves at least 25 year-round residents.
Compliance cycle means the nine-year calendar year cycle during
which public water systems must monitor. Each compliance cycle consists
of three three-year compliance periods. The first calendar year cycle
begins January 1, 1993 and ends December 31, 2001; the second begins
January 1, 2002 and ends December 31, 2010; the third begins January 1,
2011 and ends December 31, 2019.
Compliance period means a three-year calendar year period within a
compliance cycle. Each compliance cycle has three three-year compliance
periods. Within the first compliance cycle, the first compliance period
runs from January 1, 1993 to December 31, 1995; the second from January
1, 1996 to December 31, 1998; the third from January 1, 1999 to December
31, 2001.
Comprehensive performance evaluation (CPE) is a thorough review and
analysis of a treatment plant's performance-based capabilities and
associated administrative, operation and maintenance practices. It is
conducted to identify factors that may be adversely impacting a plant's
capability to achieve compliance and emphasizes approaches that can be
implemented without significant capital improvements. For purpose of
compliance with subparts P and T of this part, the comprehensive
performance evaluation must consist of at least the following
components: Assessment of plant performance; evaluation of major unit
processes; identification and prioritization of performance limiting
factors; assessment of the applicability of comprehensive technical
assistance; and preparation of a CPE report.
Confluent growth means a continuous bacterial growth covering the
entire filtration area of a membrane filter, or a portion thereof, in
which bacterial colonies are not discrete.
Contaminant means any physical, chemical, biological, or
radiological substance or matter in water.
Conventional filtration treatment means a series of processes
including coagulation, flocculation, sedimentation, and filtration
resulting in substantial particulate removal.
Corrosion inhibitor means a substance capable of reducing the
corrosivity of water toward metal plumbing materials, especially lead
and copper, by forming a protective film on the interior surface of
those materials.
CT or CTcalc is the product of ``residual disinfectant
concentration'' (C) in mg/1 determined before or at the first customer,
and the corresponding ``disinfectant contact time'' (T) in minutes,
i.e., ``C'' x ``T''. If a public water system applies disinfectants at
more than one point prior to the first customer, it must determine the
CT of each disinfectant sequence before or at the first customer to
determine the total percent inactivation or ``total inactivation
ratio.'' In determining the total inactivation ratio, the public water
system must determine the residual disinfectant concentration of each
disinfection sequence and corresponding contact time before any
subsequent disinfection application point(s). ``CT99.9'' is
the CT value required for 99.9 percent (3-log) inactivation of Giardia
lamblia cysts. CT99.9 for a variety of disinfectants and
conditions appear in tables 1.1-1.6, 2.1, and 3.1 of Sec. 141.74(b)(3).
[GRAPHIC] [TIFF OMITTED] TC15NO91.129
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is the inactivation ratio. The sum of the inactivation ratios, or total
inactivation ratio shown as
[GRAPHIC] [TIFF OMITTED] TC15NO91.130
is calculated by adding together the inactivation ratio for each
disinfection sequence. A total inactivation ratio equal to or greater
than 1.0 is assumed to provide a 3-log inactivation of Giardia lamblia
cysts.
Diatomaceous earth filtration means a process resulting in
substantial particulate removal in which (1) a precoat cake of
diatomaceous earth filter media is deposited on a support membrance
(septum), and (2) while the water is filtered by passing through the
cake on the septum, additional filter media known as body feed is
continuously added to the feed water to maintain the permeability of the
filter cake.
Direct filtration means a series of processes including coagulation
and filtration but excluding sedimentation resulting in substantial
particulate removal.
Disinfectant means any oxidant, including but not limited to
chlorine, chlorine dioxide, chloramines, and ozone added to water in any
part of the treatment or distribution process, that is intended to kill
or inactivate pathogenic microorganisms.
Disinfectant contact time (``T'' in CT calculations) means the time
in minutes that it takes for water to move from the point of
disinfectant application or the previous point of disinfectant residual
measurement to a point before or at the point where residual
disinfectant concentration (``C'') is measured. Where only one ``C'' is
measured, ``T'' is the time in minutes that it takes for water to move
from the point of disinfectant application to a point before or at where
residual disinfectant concentration (``C'') is measured. Where more than
one ``C'' is measured, ``T'' is (a) for the first measurement of ``C'',
the time in minutes that it takes for water to move from the first or
only point of disinfectant application to a point before or at the point
where the first ``C'' is measured and (b) for subsequent measurements of
``C'', the time in minutes that it takes for water to move from the
previous ``C'' measurement point to the ``C'' measurement point for
which the particular ``T'' is being calculated. Disinfectant contact
time in pipelines must be calculated based on ``plug flow'' by dividing
the internal volume of the pipe by the maximum hourly flow rate through
that pipe. Disinfectant contact time within mixing basins and storage
reservoirs must be determined by tracer studies or an equivalent
demonstration.
Disinfection means a process which inactivates pathogenic organisms
in water by chemical oxidants or equivalent agents.
Disinfection profile is a summary of Giardia lamblia inactivation
through the treatment plant. The procedure for developing a disinfection
profile is contained in Sec. 141.172 (Disinfection profiling and
benchmarking) in subpart P and Sec. Sec. 141.530-141.536 (Disinfection
profile) in subpart T of this part.
Domestic or other non-distribution system plumbing problem means a
coliform contamination problem in a public water system with more than
one service connection that is limited to the specific service
connection from which the coliform-positive sample was taken.
Dose equivalent means the product of the absorbed dose from ionizing
radiation and such factors as account for differences in biological
effective ness due to the type of radiation and its distribution in the
body as speci fied by the International Commission on Radiological Units
and Measurements (ICRU).
Effective corrosion inhibitor residual, for the purpose of subpart I
of this part only, means a concentration sufficient to form a
passivating film on the interior walls of a pipe.
Enhanced coagulation means the addition of sufficient coagulant for
improved removal of disinfection byproduct precursors by conventional
filtration treatment.
Enhanced softening means the improved removal of disinfection
byproduct precursors by precipitative softening.
Filter profile is a graphical representation of individual filter
performance,
[[Page 348]]
based on continuous turbidity measurements or total particle counts
versus time for an entire filter run, from startup to backwash
inclusively, that includes an assessment of filter performance while
another filter is being backwashed.
Filtration means a process for removing particulate matter from
water by passage through porous media.
First draw sample means a one-liter sample of tap water, collected
in accordance with Sec. 141.86(b)(2), that has been standing in
plumbing pipes at least 6 hours and is collected without flushing the
tap.
Flocculation means a process to enhance agglomeration or collection
of smaller floc particles into larger, more easily settleable particles
through gentle stirring by hydraulic or mechanical means.
GAC10 means granular activated carbon filter beds with an empty-bed
contact time of 10 minutes based on average daily flow and a carbon
reactivation frequency of every 180 days.
Ground water under the direct influence of surface water (GWUDI)
means any water beneath the surface of the ground with significant
occurrence of insects or other macroorganisms, algae, or large-diameter
pathogens such as Giardia lamblia or Cryptosporidium, or significant and
relatively rapid shifts in water characteristics such as turbidity,
temperature, conductivity, or pH which closely correlate to
climatological or surface water conditions. Direct influence must be
determined for individual sources in accordance with criteria
established by the State. The State determination of direct influence
may be based on site-specific measurements of water quality and/or
documentation of well construction characteristics and geology with
field evaluation.
Gross alpha particle activity means the total radioactivity due to
alpha particle emission as inferred from measurements on a dry sample.
Gross beta particle activity means the total radioactivity due to
beta particle emission as inferred from measurements on a dry sample.
Haloacetic acids (five) (HAA5) mean the sum of the concentrations in
milligrams per liter of the haloacetic acid compounds (monochloroacetic
acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid,
and dibromoacetic acid), rounded to two significant figures after
addition.
Halogen means one of the chemical elements chlorine, bromine or
iodine.
Initial compliance period means the first full three-year compliance
period which begins at least 18 months after promulgation, except for
contaminants listed at Sec. 141.61(a) (19)-(21), (c) (19)-(33), and
Sec. 141.62(b) (11)-(15), initial compliance period means the first
full three-year compliance period after promulgation for systems with
150 or more service connections (January 1993-December 1995), and first
full three-year compliance period after the effective date of the
regulation (January 1996-December 1998) for systems having fewer than
150 service connections.
Large water system, for the purpose of subpart I of this part only,
means a water system that serves more than 50,000 persons.
Lead service line means a service line made of lead which connects
the water main to the building inlet and any lead pigtail, gooseneck or
other fitting which is connected to such lead line.
Legionella means a genus of bacteria, some species of which have
caused a type of pneumonia called Legionnaires Disease.
Man-made beta particle and photon emitters means all radionuclides
emitting beta particles and/or photons listed in Maximum Permissible
Body Burdens and Maximum Permissible Concentration of Radionuclides in
Air or Water for Occupational Exposure, NBS Handbook 69, except the
daughter products of thorium-232, uranium-235 and uranium-238.
Maximum contaminant level means the maximum permissable level of a
contaminant in water which is delivered to any user of a public water
system.
Maximum contaminant level goal or MCLG means the maximum level of a
contaminant in drinking water at which no known or anticipated adverse
effect on the health of persons would occur, and which allows an
adequate margin of safety. Maximum contaminant level goals are
nonenforceable health goals.
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Maximum residual disinfectant level (MRDL) means a level of a
disinfectant added for water treatment that may not be exceeded at the
consumer's tap without an unacceptable possibility of adverse health
effects. For chlorine and chloramines, a PWS is in compliance with the
MRDL when the running annual average of monthly averages of samples
taken in the distribution system, computed quarterly, is less than or
equal to the MRDL. For chlorine dioxide, a PWS is in compliance with the
MRDL when daily samples are taken at the entrance to the distribution
system and no two consecutive daily samples exceed the MRDL. MRDLs are
enforceable in the same manner as maximum contaminant levels under
Section 1412 of the Safe Drinking Water Act. There is convincing
evidence that addition of a disinfectant is necessary for control of
waterborne microbial contaminants. Notwithstanding the MRDLs listed in
Sec. 141.65, operators may increase residual disinfectant levels of
chlorine or chloramines (but not chlorine dioxide) in the distribution
system to a level and for a time necessary to protect public health to
address specific microbiological contamination problems caused by
circumstances such as distribution line breaks, storm runoff events,
source water contamination, or cross-connections.
Maximum residual disinfectant level goal (MRDLG) means the maximum
level of a disinfectant added for water treatment at which no known or
anticipated adverse effect on the health of persons would occur, and
which allows an adequate margin of safety. MRDLGs are nonenforceable
health goals and do not reflect the benefit of the addition of the
chemical for control of waterborne microbial contaminants.
Maximum Total Trihalomethane Potential (MTP) means the maximum
concentration of total trihalomethanes produced in a given water
containing a disinfectant residual after 7 days at a temperature of 25
[deg]C or above.
Medium-size water system, for the purpose of subpart I of this part
only, means a water system that serves greater than 3,300 and less than
or equal to 50,000 persons.
Near the first service connection means at one of the 20 percent of
all service connections in the entire system that are nearest the water
supply treatment facility, as measured by water transport time within
the distribution system.
Non-community water system means a public water system that is not a
community water system. A non-community water system is either a
``transient non-community water system (TWS)'' or a ``non-transient non-
community water system (NTNCWS).''
Non-transient non-community water system or NTNCWS means a public
water system that is not a community water system and that regularly
serves at least 25 of the same persons over 6 months per year.
Optimal corrosion control treatment, for the purpose of subpart I of
this part only, means the corrosion control treatment that minimizes the
lead and copper concentrations at users' taps while insuring that the
treatment does not cause the water system to violate any national
primary drinking water regulations.
Performance evaluation sample means a reference sample provided to a
laboratory for the purpose of demonstrating that the laboratory can
successfully analyze the sample within limits of performance specified
by the Agency. The true value of the concentration of the reference
material is unknown to the laboratory at the time of the analysis.
Person means an individual; corporation; company; association;
partnership; municipality; or State, Federal, or tribal agency.
Picocurie (pCi) means the quantity of radioactive material producing
2.22 nuclear transformations per minute.
Point of disinfectant application is the point where the
disinfectant is applied and water downstream of that point is not
subject to recontamination by surface water runoff.
Point-of-entry treatment device (POE) is a treatment device applied
to the drinking water entering a house or building for the purpose of
reducing contaminants in the drinking water distributed throughout the
house or building.
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Point-of-use treatment device (POU) is a treat ment device applied
to a single tap used for the purpose of reducing con tam i nants in
drinking water at that one tap.
Public water system means a system for the provision to the public
of water for human consumption through pipes or, after August 5, 1998,
other constructed conveyances, if such system has at least fifteen
service connections or regularly serves an average of at least twenty-
five individuals daily at least 60 days out of the year. Such term
includes: any collection, treatment, storage, and distribution
facilities under control of the operator of such system and used
primarily in connection with such system; and any collection or
pretreatment storage facilities not under such control which are used
primarily in connection with such system. Such term does not include any
``special irrigation district.'' A public water system is either a
``community water system'' or a ``noncommunity water system.''
Rem means the unit of dose equivalent from ionizing radiation to the
total body or any internal organ or organ system. A ``millirem (mrem)''
is 1/1000 of a rem.
Repeat compliance period means any subsequent compliance period
after the initial compliance period.
Residual disinfectant concentration (``C'' in CT calculations) means
the concentration of disinfectant measured in mg/l in a representative
sample of water.
Sanitary survey means an onsite review of the water source,
facilities, equipment, operation and maintenance of a public water
system for the purpose of evaluating the adequacy of such source,
facilities, equipment, operation and maintenance for producing and
distributing safe drinking water.
Sedimentation means a process for removal of solids before
filtration by gravity or separation.
Service connection, as used in the definition of public water
system, does not include a connection to a system that delivers water by
a constructed conveyance other than a pipe if:
(1) The water is used exclusively for purposes other than
residential uses (consisting of drinking, bathing, and cooking, or other
similar uses);
(2) The State determines that alternative water to achieve the
equivalent level of public health protection provided by the applicable
national primary drinking water regulation is provided for residential
or similar uses for drinking and cooking; or
(3) The State determines that the water provided for residential or
similar uses for drinking, cooking, and bathing is centrally treated or
treated at the point of entry by the provider, a pass-through entity, or
the user to achieve the equivalent level of protection provided by the
applicable national primary drinking water regulations.
Service line sample means a one-liter sample of water collected in
accordance with Sec. 141.86(b)(3), that has been standing for at least
6 hours in a service line.
Single family structure, for the purpose of subpart I of this part
only, means a building constructed as a single-family residence that is
currently used as either a residence or a place of business.
Slow sand filtration means a process involving passage of raw water
through a bed of sand at low velocity (generally less than 0.4 m/h)
resulting in substantial particulate removal by physical and biological
mechanisms.
Small water system, for the purpose of subpart I of this part only,
means a water system that serves 3,300 persons or fewer.
Special irrigation district means an irrigation district in
existence prior to May 18, 1994 that provides primarily agricultural
service through a piped water system with only incidental residential or
similar use where the system or the residential or similar users of the
system comply with the exclusion provisions in section 1401(4)(B)(i)(II)
or (III).
Standard sample means the aliquot of finished drinking water that is
examined for the presence of coliform bacteria.
State means the agency of the State or Tribal government which has
jurisdiction over public water systems. During any period when a State
or Tribal government does not have primary enforcement responsibility
pursuant to
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section 1413 of the Act, the term ``State'' means the Regional
Administrator, U.S. Environmental Protection Agency.
Subpart H systems means public water systems using surface water or
ground water under the direct influence of surface water as a source
that are subject to the requirements of subpart H of this part.
Supplier of water means any person who owns or operates a public
water system.
Surface water means all water which is open to the atmosphere and
subject to surface runoff.
SUVA means Specific Ultraviolet Absorption at 254 nanometers (nm),
an indicator of the humic content of water. It is a calculated parameter
obtained by dividing a sample's ultraviolet absorption at a wavelength
of 254 nm (UV 254) (in m =1) by its concentration
of dissolved organic carbon (DOC) (in mg/L).
System with a single service connection means a system which
supplies drinking water to consumers via a single service line.
Too numerous to count means that the total number of bacterial
colonies exceeds 200 on a 47-mm diameter membrane filter used for
coliform detection.
Total Organic Carbon (TOC) means total organic carbon in mg/L
measured using heat, oxygen, ultraviolet irradiation, chemical oxidants,
or combinations of these oxidants that convert organic carbon to carbon
dioxide, rounded to two significant figures.
Total trihalomethanes (TTHM) means the sum of the concentration in
milligrams per liter of the trihalo methane compounds (trichloromethane
[chloro form], dibromochloromethane, bromodichloro methane and
tribromomethane [bromoform]), rounded to two significant figures.
Transient non-community water system or TWS means a non-community
water system that does not regularly serve at least 25 of the same
persons over six months per year.
Trihalomethane (THM) means one of the family of organic compounds,
named as derivatives of methane, wherein three of the four hydrogen
atoms in methane are each sub stituted by a halogen atom in the
molecular struc ture.
Uncovered finished water storage facility is a tank, reservoir, or
other facility used to store water that will undergo no further
treatment except residual disinfection and is open to the atmosphere.
Virus means a virus of fecal origin which is infectious to humans by
waterborne transmission.
Waterborne disease outbreak means the significant occurrence of
acute infectious illness, epidemiologically associated with the
ingestion of water from a public water system which is deficient in
treatment, as determined by the appropriate local or State agency.
[40 FR 59570, Dec. 24, 1975, as amended at 41 FR 28403, July 9, 1976; 44
FR 68641, Nov. 29, 1979; 51 FR 11410, Apr. 2, 1986; 52 FR 20674, June 2,
1987; 52 FR 25712, July 8, 1987; 53 FR 37410, Sept. 26, 1988; 54 FR
27526, 27562, June 29, 1989; 56 FR 3578, Jan. 30, 1991; 56 FR 26547,
June 7, 1991; 57 FR 31838, July 17, 1992; 59 FR 34322, July 1, 1994; 61
FR 24368, May 14, 1996; 63 FR 23366, Apr. 28, 1998; 63 FR 69463, 69515,
Dec. 16, 1998; 66 FR 7061, Jan. 22, 2001; 67 FR 1835, Jan. 14, 2002]