Connecticut Administrative Code › Title 22a - Environmental Protection › 426 - Connecticut Water Quality Standards › Section 22a-426-7 - Ground waters

Current through July 10, 2024
(a)
General
			 Ground Water Standards and Policies
(1)
			 The policy of the department for areas classified as GAA, GAAs, or GA shall be
			 to maintain or restore all ground water in such areas to its natural
			 quality.
(2) Notwithstanding
			 subdivision (1) of this subsection, if the Commissioner determines that, with
			 respect to a particular pollutant, restoring or maintaining natural quality at
			 a GAA, GAAs, or GA level is not technically practicable, the department's
			 policy shall be to:
(A) maintain or restore
			 water quality such that the ground water is suitable for drinking and other
			 domestic uses without treatment;
(B) maintain or restore water quality such
			 that the ground water will not adversely affect surface water quality or
			 prevent the maintenance or attainment of any designated uses of surface waters
			 to which that ground water discharges;
(C) eliminate sources of pollution to such
			 ground water to the extent that the Commissioner determines to be technically
			 practicable; and
(D) regulate
			 discharges to such ground water so as to prevent pollution.
(3) Ground water is deemed
			 suitable for drinking and other domestic uses without treatment when no
			 pollutant in such ground water:
(A) exceeds a
			 level which the Commissioner of Public Health has determined, pursuant to
			 section
			 22a-471
			 of the Connecticut General Statutes, creates or reasonably can be expected to
			 create an unacceptable risk of injury to the health or safety of persons using
			 such ground water for drinking or other personal or domestic use;
(B) is a carcinogen present at a
			 concentration associated with a 1 × 10 -6 excess
			 cancer risk;
(C) is a
			 non-carcinogen present at a level exceeding that to which the human population,
			 including sensitive subgroups, can be exposed on a daily basis without
			 appreciable risk of adverse health effects during a lifetime; or
(D) exceeds a level which the Commissioner
			 determines, in consultation with the Commissioner of Public Health, renders the
			 ground water so aesthetically impaired that a person cannot reasonably be
			 expected to consume or otherwise use it.
(4) The policy of the department in areas
			 classified as GB shall be:
(A) to eliminate
			 or reduce in ground water any pollutant which presents a hazard of fire,
			 explosion, or toxic or hazardous emission to the environment or is determined
			 by the Commissioner to otherwise pose a threat to public safety or an
			 unacceptable risk to public health;
(B) to maintain water quality such that
			 ground water will not adversely affect the quality of surface waters to which
			 such ground water discharges or prevent the maintenance or attainment of any
			 designated or existing uses of such surface waters;
(C) to maintain water quality consistent with
			 all designated and existing uses of the ground water, including its use for
			 drinking without treatment provided such ground water has been utilized, and
			 continues to be utilized, for drinking water; and
(D) to regulate discharges to the ground
			 water in order to prevent further degradation of ground water
			 quality.
(5) The policy
			 of the department in areas classified as GC shall be:
(A) to eliminate or reduce in the ground
			 water any pollutant which presents a hazard of fire, explosion, or toxic or
			 hazardous emission to the air or is determined by the Commissioner to otherwise
			 pose a threat to public safety or an unacceptable threat to public
			 health;
(B) to maintain the ground
			 water at a quality that will not adversely affect the quality of surface waters
			 to which such ground water discharges or prevent the maintenance or attainment
			 of any designated or existing uses of such surface waters; and
(C) to limit the impacts of waste discharges
			 on ground water quality to those which, despite the use of treatment
			 technology, cannot be avoided and which result from a discharge which is
			 authorized by a permit under section
			 22a-430
			 of the Connecticut General Statutes.
(6) Antidegradation Standards
(A) With respect to ground water whose
			 quality is actually higher than that reflected by the assigned classification,
			 such ground water should be maintained at its existing high quality. To
			 maintain such quality, the Commissioner may require that:
(i) a new, increased, or otherwise modified
			 discharge to such ground water shall be given treatment such that,
			 notwithstanding such classification, the actual higher quality is maintained;
			 and
(ii) if there is an unpermitted
			 release of pollutants to ground water which is classified GB but whose quality
			 is actually GA or GAA, such ground water shall be remediated to the standards
			 for Class GA or GAA.
(B)
			 The department's classification of ground water, whether as GB, GC, or
			 otherwise, conveys no right to degrade that ground water or to utilize less
			 effective treatment measures than those utilized for discharges to ground water
			 designated for use as potable water. Domestic sewage shall be given the same
			 treatment regardless of the classification of the ground water to which such
			 sewage is discharged.
(7) The Commissioner may issue a permit
			 authorizing a discharge of material to ground water, even if such discharge
			 would be inconsistent with subsections (c)(1), (c)(2), (e), or (g) of this
			 section, provided such discharge otherwise conforms with all applicable legal
			 requirements and standards, is necessary to remediate ground water pollution,
			 and is treated or managed such that, to the maximum extent practicable, the
			 discharge does not impair public health or the environment.