Rhode Island Code of Regulations › Title 250 - Department of Environmental Management › Chapter 150 - Water Resources › Subchapter 05 - Water Quality › Part 3 - Groundwater Quality Rules › Section 250-RICR-150-05-3.11 - Groundwater Quality Standards and Preventive Action Limits

Current through June 14, 2024
A. Class GAA and class GA Groundwater Quality
				  Standards: Class GAA and class GA groundwater are suitable for drinking water
				  use without treatment, and therefore, both classes are subject to the same
				  groundwater quality standards below in §§
										3.11(A)(1) through
				  (4) of this Part. Exceedances of the
				  groundwater quality standards that are determined by the Director to be caused
				  by naturally occurring conditions will not be considered a violation of the
				  groundwater quality standards. In those areas where the groundwater is
				  classified GAA or GA and the groundwater does not meet the groundwater quality
				  standards, the groundwater classification remains GAA or GA with the goal to
				  regain compliance with the groundwater quality standards.
1. Pollutants shall not be in groundwater
				  classified GAA or GA, except within an approved pollutant discharge zone or
				  residual zone (as provided for in §§
											3.12(D) and
				  (E) of this Part respectively), in any
				  concentration which will adversely affect the groundwater as a source of safe
				  and potable drinking water or which will adversely affect other beneficial uses
				  of the groundwater, to include but not be limited to recreational, agricultural
				  and industrial uses and the preservation of fish and wildlife habitat through
				  the maintenance of surface water quality.
2. The numerical groundwater quality
				  standards for specific substances in class GAA and class GA shall be the
				  federal maximum contaminant levels for drinking water established by the United
				  States Environmental Protection Agency National Primary Drinking Water
				  Regulations 40 C.F.R.
				  §§
												141.60 through
				  141.66 and
				  141.80, incorporated above at
				  §
											3.6(B) of
				  this Part. For a substance with no maximum contaminant level, the groundwater
				  quality standard for class GAA and GA groundwater shall be determined by the
				  Director on an interim basis in accordance with R.I. Gen. Laws §
											46-13.1-4, and such standard shall
				  be consistent with the contaminant level determined by the Rhode Island
				  Department of Health pursuant to R.I. Gen. Laws §
											46-13-10. The Department shall
				  notify the public of such interim standard. The Department shall initiate
				  rulemaking, pursuant to R.I. Gen. Laws §
											42-35-2.7, to incorporate a
				  standard for a substance with no maximum contaminant level into these
				  regulations within six months of making the interim determination. The interim
				  standard shall remain in effect until a final standard has been incorporated
				  into these Rules. The Director has established the following GAA and GA
				  groundwater quality standards for contaminants that do not have a maximum
				  contaminant level established:
a. Methyl
				  tertiary butyl ether (MTBE) -- 0.04 milligrams per liter;
b. Naphthalene -- 0.1 milligrams per
				  liter;
c. [PFOS] + [PFOA] + [PFNA]
				  + [PFDA] + [PFHxS] + [PFHpA] [GREATER THAN AND EQUALS TO] 20 nanograms per
				  liter
Where,
PFOS = perfluorooctane sulfonate
PFOA = perfluorooctanoic acid
PFNA = perfluorononanoic acid
PFDA = perfluorodecanoic acid
PFHxS = perfluorohexane sulfonic acid
PFHpA = perfluoroheptanoic acid
3. Pollutants shall not be in groundwater
				  classified GAA or GA that exceed levels which the Director has determined
				  render the groundwater so impaired for taste, odor or color that a person
				  cannot reasonably be expected to consume or otherwise use it.
4. Groundwater classified GAA and GA shall be
				  of a quality which the Director determines does not violate or have any
				  reasonable potential to cause a violation of surface water quality standards
				  established by the Rhode Island Water Quality Regulations Part 1 of this
				  Subchapter.
5. Groundwater
				  classified GAA and GA shall not have non-aqueous phase liquids present in
				  either a mobile or immobile state at or below the surface of the water
				  table.