Connecticut Administrative Code › Title 19 - Public Health and Safety › 13-B › Chapter II - ENVIRONMENTAL HEALTH › Standards for Quality of Public Drinking Water › Section 19-13-B102 - Standards for quality of public drinking water

Current through July 10, 2024
(a)
				  Definitions.
As used in this section:
(1) "Action level" means the concentration of
				  lead or copper in water specified in subsection (j)(6)(B) of this section which
				  determines, in some cases, the treatment requirements contained in subsection
				  (j)(6) of this section that a system is required to complete;
(2) "Active source of supply" means all
				  springs, streams, watercourses, brooks, rivers, lakes, ponds, wells, or
				  underground water from which water is taken on a regular or periodic basis for
				  water supply purposes. A number of wells drawing water from a single aquifer or
				  more than 1 surface water body or a combination of surface water and ground
				  water sources connected to a common distribution system may be considered a
				  single source of supply;
(3)
				  "Analyte" has the same meaning as provided in section 19a-29a of the
				  Connecticut General Statutes;
(4)
				  "Annual average" means the arithmetic average of the quarterly averages of 4
				  consecutive quarters of monitoring;
(5) "Bag filters" means pressure-driven
				  separation devices that remove particulate matter larger than 1 micrometer
				  using an engineered porous filtration media and are typically constructed of a
				  non-rigid, fabric filtration media housed in a pressure vessel in which the
				  direction of flow is from the inside of the bag to the outside;
(6) "Bank filtration" means a water treatment
				  process that uses a well to recover surface water that has naturally
				  infiltrated into ground water through a river bed or bank(s). Infiltration is
				  typically enhanced by the hydraulic gradient imposed by a nearby pumping water
				  supply or other well(s);
(7)
				  "Cartridge filters" means pressure-driven separation devices that remove
				  particulate matter larger than 1 micrometer using an engineered porous
				  filtration media and are typically constructed as rigid or semi-rigid,
				  self-supporting filter elements housed in pressure vessels in which flow is
				  from the outside of the cartridge to the inside;
(8) "Certified distribution system operator"
				  means an operator who has met the education, experience, and examination
				  requirements specified in section
				  25-32-11
				  of the Regulations of Connecticut State Agencies and has been certified by the
				  department;
(9) "Certified
				  operator" means an operator who has met the education, experience, and
				  examination requirements specified in sections
				  25-32-7a
				  to
				  25-32-14,
				  inclusive, of the Regulations of Connecticut State Agencies and has been
				  certified by the department;
(10)
				  "Certified water treatment plant operator" means an operator who has met the
				  education, experience, and examination requirements of section
				  25-32-9
				  of the Regulations of Connecticut State Agencies and has been certified by the
				  department;
(11) "CFR" means Code
				  of Federal Regulations;
(12) "Clean
				  compliance history" means a record of no maximum contaminant level violations
				  under subsection (e)(7) of this section, no monitoring violations under
				  subsection (x) of this section, and no coliform treatment technique trigger
				  exceedances or treatment technique violations under subsection (x) of this
				  section;
(13) "Coagulation" means a
				  process using coagulant chemicals and mixing by which colloidal and suspended
				  materials are destabilized and agglomerated into flocs;
(14) "Coliform" means a group of bacteria
				  found in the intestines of warm-blooded animals (including humans) and found in
				  plants, soil, air, and water;
(15)
				  "Combined distribution system" means the interconnected distribution system
				  consisting of the distribution systems of wholesale systems and of the
				  consecutive public water systems that receive finished water;
(16) "Community water system" or "CWS" means
				  a public water system that regularly serves at least 25 year-round
				  residents;
(17) "Compliance cycle"
				  means the 9 calendar-year cycle during which public water systems shall
				  monitor. Each compliance cycle consists of 3 3-year compliance periods. The
				  first calendar year cycle began on January 1, 1993 and ended on December 31,
				  2001;
(18) "Compliance period"
				  means a 3 calendar-year period within a compliance cycle;
(19) "Comprehensive performance evaluation"
				  or "CPE" means 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.
				  The comprehensive performance evaluation shall comprise of a written report
				  consisting of at least the following components:
(A) Assessment of plant
				  performance;
(B) Evaluation of
				  major unit processes;
(C)
				  Identification and prioritization of performance limiting factors;
(D) Assessment of the applicability of
				  comprehensive technical assistance;
(E) Identification of improvements selected
				  by a public water system to enhance the treatment plant's capability to achieve
				  compliance; and
(F) A schedule of
				  dates for the implementation of the improvements;
(20) "Comprehensive technical assistance"
				  means a performance improvement phase that is implemented using results from
				  the comprehensive performance evaluation;
(21) "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;
(22) "Consecutive public water system" or
				  "consecutive system" means a public water system that receives some or all of
				  its finished water from 1 or more wholesale systems. Delivery may be through a
				  direct connection or through the distribution system of 1 or more consecutive
				  public water systems;
(23)
				  "Consultation" means a telephone call, electronic mail exchange or meeting at
				  which the public water system reports to the department the nature of the
				  violation and the department, in turn, determines the action that shall be
				  taken by the public water system;
(24) "Consumer" has the same meaning as
				  provided in section 25-32a of the Connecticut General Statutes;
(25) "Contaminant" means any physical,
				  chemical, biological, or radiological substance or matter in water;
(26) "Conventional filtration treatment"
				  means a series of processes including coagulation, flocculation, sedimentation
				  or dissolved air flotation, and filtration resulting in substantial particulate
				  removal;
(27) "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;
(28) "Cryptosporidium" means a protozoan
				  found in the intestines of livestock and in water contaminated by sewage or
				  runoff containing animal waste;
(29) "CT" or "CTcalc" means the product of
				  the "residual disinfectant concentration" (C) in milligrams per liter
				  determined before or at the first consumer, and the corresponding "disinfectant
				  contact time" (T) in minutes (i.e., "C" X "T"). If a public water system
				  applies disinfectants at more than 1 point prior to the first consumer, it
				  shall determine the CT of each disinfectant sequence before or at the first
				  consumer to determine the total percent inactivation;
(30) "CT99.9" means the CT value required for
				  99.9 percent (3 log) inactivation of Giardia lamblia cysts;
(31) "Department" means the Department of
				  Public Health;
(32) "Diatomaceous
				  earth filtration" means a process resulting in substantial particulate removal
				  in which a pre-coat cake of diatomaceous earth filter media is deposited on a
				  support membrane (septum), and 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;
(33) "Direct filtration"
				  means a series of processes including coagulation and filtration, but excluding
				  sedimentation, resulting in substantial particulate removal;
(34) "Direct integrity test" means a physical
				  test applied to a membrane filtration unit in order to identify and isolate
				  integrity breaches (i.e., 1 or more leaks that could result in contamination of
				  the filtrate);
(35) "Disinfectant
				  contact time" ("T" in CTcalc) 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;
(A) Where only 1 "C" is measured (single
				  application point), "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 which
				  residual disinfectant concentration ("C") is measured;
(B) Where more than 1 "C" is measured
				  (multiple application points), "T" is:
(i) For
				  the first measurement of "C", the time in minutes that it takes for water to
				  move from the first point of disinfectant application to a point before or at
				  the point where the first "C" is measured; and
(ii) 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 subsequent "T" is
				  being calculated;
(C)
				  Disinfectant contact time in pipelines shall be calculated based on plug flow
				  by dividing the internal volume of the pipe by the maximum hourly flow rate
				  through that pipe; and
(D)
				  Disinfectant contact time within mixing basins, clearwells, and storage
				  reservoirs shall be determined by tracer studies or an equivalent
				  demonstration;
(36)
				  "Disinfection" means a process which inactivates microbial pathogens in water
				  by chemical oxidants or equivalent agents;
(37) "Disinfection profile" means a summary
				  of daily giardia lamblia inactivation through the treatment plant;
(38) "Distribution system" means any
				  combination of pipes, tanks, pumps, or similar devices or mechanisms that
				  deliver water from the sources, treatment facilities or storage facilities to
				  the consumer;
(39) "Domestic or
				  other non-distribution system plumbing problem" means a coliform contamination
				  problem in a public water system with more than 1 service connection that is
				  limited to the specific service connection from which the coliform-positive
				  sample was taken;
(40) "Dose
				  equivalent" means the product of the absorbed dose from ionizing radiation and
				  such factors as account for differences in biological effectiveness due to the
				  type of radiation and its distribution in the body as specified by the
				  International Commission on Radiation Units and Measurements;
(41) "Drinking water" means water, treated or
				  untreated, intended for human consumption, which includes drinking, bathing,
				  showering, cooking, dishwashing and maintaining oral hygiene;
(42) "Dual sample set" means a set of 2
				  samples collected at the same time and same location, with 1 sample analyzed
				  for total trihalomethanes (TTHM) and the other sample analyzed for total
				  haloacetic acids (HAA5);
(43) "EC
				  medium plus MUG" means analytical tests for waterborne bacteria as specified in
				  40 CFR
				  141.21(f), as amended from
				  time to time;
(44) "E. coli" or
				  "Escherichia coli" means a species of fecal coliform that thrives at the body
				  temperature of mammals;
(45) "End
				  of the distribution system" means the last service connection on a dead-end
				  water main;
(46) "Enhanced
				  coagulation" means the addition of sufficient coagulant for improved removal of
				  disinfection byproduct precursors by conventional filtration
				  treatment;
(47) "Enhanced
				  softening" means the improved removal of disinfection byproduct precursors by
				  precipitative softening;
(48) "EPA"
				  means the United States Environmental Protection Agency;
(49) "Fecal coliform" means bacteria that
				  grows in the colon of mammals and is transmitted through fecal
				  material;
(50) "Filter profile"
				  means a graphical representation of individual filter performance, 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;
(51) "Filtration" means
				  a process for removing particulate matter from water by passage through porous
				  media;
(52) "Finished water" means
				  water that is introduced into the distribution system of a public water system
				  and is intended for distribution and consumption without further treatment,
				  except as treatment is necessary to maintain water quality in the distribution
				  system (e.g., booster disinfection, addition of corrosion control
				  chemicals);
(53) "First-draw
				  sample" means a 1-liter sample of tap water, collected in accordance with
				  subsection (e)(8)(B)(ii) of this section, that has been standing in plumbing
				  pipes at least 6 hours and is collected without flushing the tap;
(54) "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;
(55) "Flowing stream" means
				  a course of running water flowing in a definite channel;
(56) "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, except that the
				  reactivation frequency for GAC10 used as a best available technology for
				  compliance with the MCLs under subsection (e)(11)(B)(i) of this section is 120
				  days;
(57) "GAC20" means granular
				  activated carbon filter beds with an empty-bed contact time of 20 minutes based
				  on average daily flow and a carbon reactivation frequency of every 240
				  days;
(58) "Gross alpha particle
				  activity" means the total radioactivity due to alpha particle emission as
				  inferred from measurements on a dry sample;
(59) "Gross beta particle activity" means the
				  total radioactivity due to beta particle emissions as inferred from
				  measurements on a dry sample;
(60)
				  "Ground water" means the supply of source water under the earth's surface that
				  is not under the influence of surface water;
(61) "Ground water system" means a public
				  water system that provides ground water, in whole or part, directly to
				  consumers but does not include a public water system that combines ground water
				  with surface water prior to treatment or ground water under the direct
				  influence of surface water;
(62)
				  "Ground water under the direct influence of surface water" or "GWUDI" means any
				  water beneath the surface of the ground with either a 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. The
				  department determination of direct influence may be based on site-specific
				  measurements of water quality or documentation of well construction
				  characteristics and geology, or both, which may include a field
				  evaluation;
(63) "Haloacetic acid
				  five" or "HAA5" means 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
				  2 significant figures;
(64)
				  "Hydrogeologic sensitivity assessment" or "HSA" means the department's act of
				  making a determination of whether a ground water system obtains water from
				  hydrogeologically sensitive settings taking into account information regarding
				  the specific aquifer from which the system is drawing water, well construction
				  records, characterization of the hydrogeology of the source aquifer, and
				  whether the aquifer has a hydrogeologic barrier that would prevent the vertical
				  movement of microbial pathogens from the surface into the aquifer;
(65) "Lake" means a natural or man-made basin
				  or hollow on the earth's surface, including a reservoir, in which water
				  collects or is stored that may or may not have a current or single direction of
				  flow;
(66) "Large", when used in
				  reference to a public water system, means serving more than 50,000
				  persons;
(67) "Lead service line"
				  means a service line made of lead that connects the water main to a building
				  inlet and any lead pigtail, gooseneck or other fitting connected to such lead
				  line;
(68) "Legionella" means a
				  genus of bacteria, some species of which have caused a type of pneumonia called
				  legionnaires' disease;
(69) "Level
				  1 assessment" means an evaluation conducted pursuant to subsection (x) of this
				  section by a public water system or the department, if the department elects to
				  conduct the evaluation, to identify the possible presence of sanitary defects,
				  defects in distribution system coliform monitoring practices, and, when
				  possible, the likely reason that the public water system triggered the
				  evaluation;
(70) "Level 2
				  assessment" means an evaluation conducted pursuant to subsection (x) of this
				  section by a level 2 assessor or the department, if the department elects to
				  conduct the evaluation, to identify the possible presence of sanitary defects,
				  defects in distribution system coliform monitoring practices, and, when
				  possible, the likely reason that the public water system triggered the
				  evaluation;
(71) "Level 2 assessor"
				  means a professional civil or environmental engineer licensed in accordance
				  with chapter 391 of the Connecticut General Statutes with knowledge of the
				  regulation of public water systems in the state of Connecticut, a certified
				  distribution system operator that is certified at the classification level
				  equal to or higher than the classification level for the distribution system at
				  the public water system at which the assessment is being conducted, or a
				  certified water treatment plant operator that is certified at the
				  classification level equal to or higher than the classification level for the
				  water treatment plant at the public water system at which the assessment is
				  being conducted who shall:
(A) Have
				  successfully completed a 6 hour level 2 assessment training provided by the
				  department prior to conducting a level 2 assessment; and
(B) Not be an employee of the public water
				  system at which the assessment is being conducted;
(72) "Local director of health" means a city,
				  town, borough, or district director of health or the director of health's
				  authorized agent;
(73) "Locational
				  running annual average" or "LRAA" means the average of sample analytical
				  results for samples taken at a particular monitoring location during the
				  previous 4 calendar quarters;
(74)
				  "Man-made beta particles and photon emitters" means all radionuclides emitting
				  beta particles or photons, or both, listed in Maximum Permissible Body Burdens
				  and Maximum Concentrations of Radionuclides in Air or Water for Occupational
				  Exposure, National Bureau of Standards Handbook 69, except the daughter
				  products of thorium-232, uranium-235 and uranium-238;
(75) "Maximum contaminant level" or "MCL"
				  means the maximum permissible level of a contaminant in water that is delivered
				  to any consumer of a public water system;
(76) "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
				  non-enforceable health goals;
(77)
				  "Maximum residual disinfectant level" or "MRDL" means a level of a disinfectant
				  added for water treatment that shall not be exceeded at the consumer's tap
				  without an unacceptable possibility of adverse health effects. MRDL is
				  enforceable in the same manner as maximum contaminant level;
(78) "Maximum residual disinfectant level
				  goal" or "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. MRDLG is a
				  non-enforceable health goal and does not reflect the benefit of the addition of
				  the chemical for control of waterborne microbial contaminants;
(79) "Medium-size" means serving more than
				  3,300 and less than or equal to 50,000 persons;
(80) "Membrane filtration" means a pressure
				  or vacuum driven separation process in which particulate matter larger than 1
				  micrometer is rejected by an engineered barrier, primarily through a
				  size-exclusion mechanism, and which has a measurable removal efficiency of a
				  target organism that can be verified through the application of a direct
				  integrity test. This definition includes the common membrane technologies of
				  microfiltration, ultrafiltration, nanofiltration, and reverse
				  osmosis;
(81) "Method detection
				  limit" or "MDL" means the minimum concentration of a substance that can be
				  measured and reported with 99 percent confidence that the true value is greater
				  than 0;
(82) "Mg/l" means
				  milligrams per liter;
(83)
				  "Microbial pathogen" means a microorganism, such as a bacterium, virus or
				  parasite, that can cause infection and illness in humans, including, but not
				  limited to: Echovirus, Coxsackie viruses, Hepatitis A and E, Rotavirus,
				  Norovirus, E. coli, Salmonella species, Shigella species, and Vibrio
				  cholerae;
(84) "Molecular Weight
				  Cutoff" or "MWCO" means a measure of the removal characteristic of a membrane
				  in terms of atomic weight or mass, as opposed to pore size, that is typically
				  measured in terms of Daltons;
(85)
				  "Near the first service connection" means at 1 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;
(86) "Non-community water
				  system" means a public water system that serves at least 25 persons at least 60
				  days out of the year and is not a community water system;
(87) "Non-transient non-community water
				  system" or "NTNC" means a public water system that is not a community system
				  and that regularly serves at least 25 of the same persons over 6 months per
				  year;
(88) "Notification level"
				  means the level of a contaminant that if exceeded shall require public
				  notification by a public water system to its consumers;
(89) "Optimal corrosion control treatment"
				  means the corrosion control treatment that minimizes the lead and copper
				  concentrations at users' taps while ensuring that the treatment does not cause
				  the community water system or non-transient non-community water system to
				  violate any drinking water statutes or regulations;
(90) "Picocurie" or "pCi" means the quantity
				  of radioactive material producing 2.22 nuclear transformations per
				  minute;
(91) "Physical parameters"
				  means color, turbidity, pH, and odor;
(92) "Physical parameter level goal" means
				  the level or range for physical parameters recommended by the
				  department;
(93) "Plant intake"
				  means the works or structures at the head of a conduit through which water is
				  diverted from a source (e.g., river or lake) into the treatment
				  plant;
(94) "Point of disinfectant
				  application" means the point where the disinfectant is applied and water
				  downstream of that point is not subject to recontamination by surface
				  water;
(95) "Point of entry" or
				  "entry point" means a location on an active source of supply that is after any
				  treatment and before the entrance to the distribution system;
(96) "Practical quantification level" or
				  "PQL" means the lowest concentration that can be reliably measured within
				  specific limits of precision and accuracy during routine laboratory operating
				  conditions;
(97) "Presedimentation"
				  means a preliminary treatment process used to remove gravel, sand and other
				  particulate material from the source water through settling before the water
				  enters the primary clarification and filtration processes in a treatment
				  plant;
(98) "Public water system"
				  or "system" means any water company supplying drinking water to 15 or more
				  consumers or 25 or more persons, based on the "Design Population" as defined in
				  section
				  16-262m-8(a)(3)
				  of the Regulations of Connecticut State Agencies, daily at least 60 days of the
				  year that does not meet all of the following conditions:
(A) Consists only of distribution and storage
				  facilities;
(B) Does not have any
				  treatment facilities, other than those for non-potable use;
(C) Obtains all of its water from, but is not
				  owned or operated by, a public water system;
(D) Does not separately bill the consumers
				  for water use or consumption; and
(E) Is not a carrier which conveys passengers
				  in interstate commerce;
(99) "Raw water" means water in its natural
				  state on the surface of the earth or underground;
(100) "Repeat sample" means a sample that is
				  collected as a result of a total coliform-positive routine sample;
(101) "Reservoir" means a natural or man-made
				  basin or hollow on the earth's surface, including a lake, in which water
				  collects or is stored that may or may not have a current or single direction of
				  flow;
(102) "Residual disinfectant
				  concentration" or "RDC" ("C" in CTcalc) means the concentration of disinfectant
				  measured in mg/l in a representative sample of water;
(103) "Routine sample" means a sample that is
				  collected at a location and frequency as specified in a system's sample siting
				  plan;
(104) "Sanitarian" means a
				  person who is trained in environmental health and who is qualified to carry out
				  educational and investigational duties in the fields of environmental health
				  such as investigation of air, water, sewage, foodstuffs, housing and refuse by
				  observing, sampling, testing and reporting; and who is licensed pursuant to
				  section 20-361 of the Connecticut General Statutes;
(105) "Sanitary defect" means a defect that
				  is providing, or has the potential for providing, a pathway of entry for
				  microbial contamination into the distribution system or that is indicative of a
				  failure or imminent failure in a barrier that is already in place;
(106) "Sanitary survey" means a review of a
				  public water system by the department to evaluate the adequacy of the system,
				  its sources and operations and the distribution of safe drinking
				  water;
(107) "Seasonal system"
				  means a non-community water system that is not operated as a public water
				  system on a year-round basis and starts up at the beginning of each operating
				  season and shuts down by depressurizing and dewatering all or a portion of its
				  distribution system at the end of each operating season;
(108) "Sedimentation" means a process for
				  removal of solids before filtration by gravity or separation;
(109) "Self assessment" means an assessment
				  which shall comprise a written report consisting of at least the following
				  components:
(A) Assessment of filter
				  performance;
(B) Development of a
				  filter profile;
(C) Identification
				  and prioritization of factors limiting filter performance;
(D) Assessment of the applicability of
				  improvements;
(E) Identification of
				  improvements selected by a public water system to enhance filtration and
				  achieve compliance; and
(F) A
				  schedule of dates for the implementation of the improvements;
(110) "Service line sample" means
				  a 1 liter sample of water, collected in accordance with subsection
				  (e)(8)(B)(iii) of this section, that has been standing for at least 6 hours in
				  a service line;
(111) "Significant
				  change to disinfection practice" means 1 of the following changes:
(A) Changes to the point of
				  disinfection;
(B) Changes to the
				  disinfectant(s) used in the treatment plant;
(C) Changes to the disinfection process;
				  or
(D) Any other modification
				  identified by the department that has or may have a significant impact on
				  disinfection practices or the effectiveness of such practices, or
				  both;
(112) "Significant
				  deficiency" means any situation, practice, or condition in a public water
				  system with respect to design, operation, maintenance, or administration that
				  the department determines to be causing, or has the potential for causing,
				  risks to health or safety of the public served by the system. Significant
				  deficiencies shall include, but are not limited to, defects in design,
				  operation, or maintenance, or a failure or malfunction of the sources,
				  treatment, including violations of subsection (j)(2) of this section, storage,
				  or distribution system that the department determines to be causing, or has the
				  potential for causing, the introduction of fecal contamination into the water
				  delivered to consumers;
(113)
				  "Single family structure" means a building constructed as a single-family
				  residence that is currently used as either a residence or a place of
				  business;
(114) "Slow sand
				  filtration" means a process involving passage of raw water through a bed of
				  sand at low velocity (generally less than 0.16 gallons per minute per square
				  foot), resulting in substantial particulate removal by physical and biological
				  mechanisms;
(115) "Small" means
				  serving 3,300 persons or fewer;
(116) "Source water" means raw water before
				  any kind or type of treatment at the source of supply;
(117) "Special purpose sample" means a sample
				  that is taken:
(A) To determine whether
				  disinfection practices are sufficient following routine maintenance work, such
				  as pipe placement, replacement, or repair, on the distribution system;
				  or
(B) As part of a system's start
				  up procedure under subsection (x) of this section and that is not collected in
				  accordance with a system's sampling plan under subsection (x) of this
				  section;
(118) "Subpart
				  H system" means a public water system that is supplied by a surface water or
				  ground water under the direct influence of surface water source, or
				  both;
(119) "Surface water" means
				  all water that is open to the atmosphere and subject to surface
				  runoff;
(120) "SUVA" means specific
				  ultraviolet absorption at 254 nanometers (nm), an indicator of the humic
				  content of water. 1 nm is equal to 1 billionth
				  (10-9) of a meter. It is a calculated parameter
				  obtained by dividing a sample's ultraviolet absorption at a wavelength of 254
				  nm (UV254) (in m-1) by its concentration of
				  dissolved organic carbon (DOC) in mg/l;
(121) "System with a single service
				  connection" means a system that supplies drinking water to consumers via a
				  single service line;
(122) "Tier 1
				  notice" means a notice that a public water system is required to provide for
				  the violations and other situations in subparagraphs (A) through (G),
				  inclusive, of this subdivision:
(A) Violation
				  of the maximum contaminant level for total coliforms when fecal coliform or E.
				  coli are present in the distribution system, when the public water system fails
				  to test for fecal coliforms or E. coli when any repeat sample tests positive
				  for coliform, failure to comply with the maximum contaminant level for E. coli
				  for samples taken under the provisions of subsection (x) of this
				  section;
(B) Violation of the
				  maximum contaminant level for nitrate, nitrite, or total nitrate and nitrite,
				  or when the public water system fails to take a confirmation sample not later
				  than 24 hours after the public water system's receipt of the first sample
				  showing an exceedance of the nitrate or nitrite maximum contaminant
				  level;
(C) Violation of the maximum
				  residual disinfectant level for chlorine dioxide when 1 or more samples taken
				  in the distribution system the day following an exceedance of the maximum
				  residual disinfectant level at the entrance of the distribution system exceed
				  the maximum residual disinfectant level, or when the public water system does
				  not take the required samples in the distribution system;
(D) Violation of the maximum contaminant
				  level for turbidity as specified in subsections (e)(7)(H)(ii), (j)(2)(D) and
				  (j)(4) of this section, where the department determines after consultation with
				  the public water system that the violation of the maximum contaminant level for
				  turbidity combined with other site-specific information indicate that potential
				  pathogens may have passed the point of entry to the distribution system, or
				  where the public water system does not consult with the department not later
				  than 24 hours after the public water system learns of the violation;
(E) Occurrence of a waterborne disease
				  outbreak, or other waterborne emergency, including, but not limited to, a
				  failure or significant interruption in key water treatment processes, a natural
				  disaster that disrupts the water supply or distribution system, or a chemical
				  spill or unexpected loading of possible pathogens into the source water that
				  significantly increases the potential for drinking water
				  contamination;
(F) Other violations
				  or situations with significant potential to have serious adverse effects on
				  human health as a result of short-term exposure, as determined by the
				  department based on available scientific and epidemiological findings, and
				  including, but not limited to, the detection of any chemical listed in
				  subsections (e)(2) through (e)(4), inclusive, of this section at a level that
				  is determined by the department based on available scientific and
				  epidemiological findings to have serious adverse effects on human health as a
				  result of short-term exposure ; or
(G) Detection of E. coli, enterococci, or
				  coliphage in ground water source samples as specified in subsections (e)(12)(C)
				  and (D) of this section.
(123) "Tier 2 notice" means a notice that a
				  public water system is required to provide for the violations and other
				  situations in subparagraphs (A) through (D), inclusive, of this subdivision:
(A) All violations of the maximum contaminant
				  level, maximum residual disinfectant level or treatment technique requirements,
				  except where a tier 1 notice is required ;
(B) Violations of monitoring and testing
				  procedure requirements for chlorine dioxide, except where a tier 1 or a tier 3
				  notice is required;
(C) Failure to
				  comply with the terms and conditions of any variance, order, consent order,
				  consent agreement or exemption; or
(D) Failure to take corrective action or
				  failure to maintain at least 4 log treatment of viruses using inactivation,
				  removal, or a department-approved combination of 4 log virus inactivation and
				  removal before or at the first consumer under subsections (e)(7)(E)(vi) or
				  (j)(14) of this section.
(124) "Tier 3 notice" means a notice that a
				  public water system is required to provide for the violations and other
				  situations in subparagraphs (A) through (F), inclusive, of this subdivision:
(A) Violation of a monitoring requirement,
				  except where a tier 1 notice or a tier 2 notice is required;
(B) Failure to comply with a testing
				  procedure requirement, except where a tier 1 notice or a tier 2 notice is
				  required;
(C) Operation under an
				  administrative order, variance, or an exemption;
(D) Failure to provide the notice of the
				  availability of unregulated contaminant monitoring results, as required under
				  40
				  CFR 141.207, as amended from time to time;
(E) Exceedance of the fluoride
				  secondary maximum contaminant level, as required under
				  40 CFR
				  141.208, as amended from time to time;
				  or
(F) Violation of a reporting or
				  record-keeping requirement under subsection (x) of this section.
(125) "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;
(126) "Total organic carbon" or "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 2 significant figures;
(127) "Total trihalomethanes" or "TTHM" means
				  the sum of the concentrations in milligrams per liter of bromodichloromethane,
				  dibromochloromethane, tribromoethane (bromoform) and trichloromethane
				  (chloroform) rounded, to 2 significant figures;
(128) "Transient non-community water system"
				  or "TNC" means a non-community water system that does not meet the definition
				  of a non-transient non-community water system;
(129) "Treatment" means the process of
				  altering the physical, chemical, biological or radiological quality of source
				  water for use as drinking water;
(130) "Treatment technique" means a specific
				  treatment method required by the department to control the level of
				  contaminants in drinking water;
(131) "Two-stage lime softening" means a
				  process in which chemical addition and hardness precipitation occur in each of
				  2 distinct unit clarification processes in series prior to
				  filtration;
(132) "Uncovered
				  finished water clearwell, tank or basin" means a container used to store water
				  that shall undergo no further treatment to reduce microbial pathogens, except
				  residual disinfection, and is directly open to the atmosphere;
(133) "Virus" means a microorganism of fecal
				  origin which is infectious to humans by waterborne transmission;
(134) "Water company" has the same meaning as
				  provided in section 25-32a of the Connecticut General Statutes;
(135) "Waterborne disease outbreak" means the
				  significant occurrence of acute infectious illness, epidemiologically
				  associated with the ingestion of water from a public water system as determined
				  by the department;
(136) "Wholesale
				  system" means a public water system that treats source water as necessary to
				  produce finished water and then delivers some or all of that finished water to
				  another public water system. Delivery may be through a direct connection or
				  through the distribution system of 1 or more consecutive public water systems;
				  and
(137) "Zone of influence" means
				  the land area that directly overlies and has the same horizontal extent as the
				  part of the water table or other potentiometric surface that is perceptibly
				  lowered by the withdrawal of water. The zone of influence delineated by the use
				  of modeling is that area of land in which the water table or potentiometric
				  surface is lowered by at least 0.5 foot. In the event of inadequate information
				  and data to delineate the zone of influence, a radius of 1 mile shall be
				  utilized for unconsolidated aquifer ground water sources and a radius of 1,000
				  feet shall be utilized for confined and bedrock aquifer ground water sources.