Underground source of drinking water

{
  "id": "MLC-T-ENV-029055",
  "term": "Underground source of drinking water",
  "field": "Environment",
  "term_source": "Underground Source of Drinking Water",
  "definition": "1. An aquifer or portion of an aquifer that supplies any public water system or that contains a sufficient quantity of ground water to supply a public water system, and currently supplies drinking water for human consumption, or that contains fewer than 10,000 mg/l total dissolved solids and is not an exempted aquifer.\n\n2. An Underground Source of Drinking Water as defined in Title 40, Code of Federal Regulations (40 CFR) Section 144.3 is an aquifer or part of an aquifer which: (a) supplies any public water system, or contains a sufficient quantity of ground water to supply a public water system and currently supplies drinking water for human consumption or contains fewer than 10,000 milligrams/liter of Total Dissolved Solids (TDS); and (b) is not an exempted aquifer. An \"exempted aquifer\" is part or all of an aquifer which meets the definition of a USDW but which has been exempted according to the criteria found in 40 CFR Section 146.4, which specifies that the aquifer does not currently serve as a source of drinking water, and the aquifer cannot now and will not in the future serve as a source of drinking water for one of the following reasons: 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; 4. It is located over a Class III well mining area subject to subsidence or catastrophic collapse; 5. The total dissolved solids content of the ground water is more than 3,000 and less than 10,000 milligrams/liter and it is not reasonably expected to supply a public water system.\n\n3. An aquifer currently being used as a source of drinking water or containing a sufficient quantity of ground water to supply a public water system. USDWs have a total dissolved solids content of 10,000 milligrams per liter or less and are not aquifers exempted from protection under the Safe Drinking Water Act.\n\n4. An aquifer currently being used as a source of drinkingwater or containing a sufficient quantity of ground water to supply a public water system. USDWs have a total dissolved solids content of 10,000 milligrams per liter or less and are not aquifersexempted from protection under the Safe Drinking Water Act. (40 CFR 144.3) (2)\n\n5. Aquifer or its portion: (1)(i) Which supplies any public water system as defined in § 141.2 of this chapter; or (ii) Which contains a sufficient quantity of groundwater to supply a public water system; and (A) Currently supplies drinking water for human consumption; or (B) Contains fewer than 10,000 mg/l total dissolved solids; and (2) Which is not an exempted aquifer as defined in § 144.7 of this chapter.\n\n6. Aquifer or its portion: (a)(1) Which supplies any public water system; or (2) Which contains a sufficient quantity of ground water to supply a public water system; and (i) Currently supplies drinking water for human consumption; or (ii) Contains fewer than 10,000 mg/l total dissolved solids; and (b) Which is not an exempted aquifer.\n\n7. Aquifer or its portion: (1)(i) Which supplies any public water system; or (ii) Which contains a sufficient quantity of ground water to supply a public water system; and (A) Currently supplies drinking water for human consumption; or (B) Contains fewer than 10,000 mg/l total dissolved solids; and (2) Which is not an exempted aquifer.\n\n8. Aquifer currently being used as a source of drinking water or containing a sufficient quantity of ground water to supply a public water system. USDWs have a total dissolved solids content of 10,000 milligrams per liter or less and are not aquifers exempted from protection under the Safe Drinking Water Act.",
  "abbreviation": "USDW",
  "subject": "Natural environments",
  "references": [
    "Underground Injection Control Glossary",
    "Underground Injection Control Terms",
    "40 CFR 144.3",
    "EPA Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: Progress Report at http://www.epa.gov/hfstudy/pdfs/hf-report20121214.pdf",
    "40 CFR 192.01 (CFR 2018)",
    "40 CFR 144.3 (CFR 2018); 40 CFR 270.2 (CFR 2018)",
    "40 CFR 146.3 (CFR 2018)",
    "40 CFR 144.3; HF Impacts Study Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/underground-source-of-drinking-water/"
}