part_subject: "UNDERGROUND INJECTION CONTROL PROGRAM: CRITERIA AND STANDARDS"
subpart_code: "A"
subpart_subject: "General Provisions"
section_number: "146.4"
section_subject: "Criteria for exempted aquifers."
cfr_reference: "40 CFR 146.4"
title_name: "Title 40"
title_subject: "Protection of Environment"
parts_covered: "Parts 136 to 149"
revised_date: "Revised as of July 1, 2019"
publication_date: "As of July 1, 2019"
contains_description: "Containing a codification of documents of general applicability and future effect"
publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"
---
An aquifer or a portion thereof which meets the criteria for an “underground source of drinking water” in § 146.3 may be determined under § 144.7 of this chapter to be an “exempted aquifer” for Class I-V wells if it meets the criteria in paragraphs (a) through (c) of this section. Class VI wells must meet the criteria under paragraph (d) of this section:
(a)It does not currently serve as a source of drinking water; and
(b)It cannot now and will not in the future serve as a source of drinking water because:
(1)It is mineral, hydrocarbon or geothermal energy producing, or can be demonstrated by a permit applicant as part of a permit application for a Class II or III operation to contain minerals or hydrocarbons that considering their quantity and location are expected to be commercially producible.
(2)It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical;
(3)It is so contaminated that it would be economically or technologically impractical to render that water fit for human consumption; or
(4)It is located over a Class III well mining area subject to subsidence or catastrophic collapse; or
(c)The total dissolved solids content of the ground water is more than 3,000 and less than 10,000 mg/l and it is not reasonably expected to supply a public water system.
(d)The areal extent of an aquifer exemption for a Class II enhanced oil recovery or enhanced gas recovery well may be expanded for the exclusive purpose of Class VI injection for geologic sequestration under § 144.7(d) of this chapter if it meets the following criteria:
(1)It does not currently serve as a source of drinking water; and
(2)The total dissolved solids content of the ground water is more than 3,000 mg/l and less than 10,000 mg/l; and
(3)It is not reasonably expected to supply a public water system.