Definition(s)
Underground Source of Drinking Water (USDW)
An aquifer or its portion which supplies any public water supply system or currently supplies drinking water for human consumption or which contains sufficient water to supply a public water system or has a total dissolved solids (TDS) concentration of less than 10,000 mg/l. The EPA may exempt an aquifer if it will not serve as a source of drinking water in the future because it is economically or technically impractical to recover the water or to render it fit for human consumption or because the aquifer produces or is expected to commercially produce minerals, hydrocarbons, or geothermal energy.
While the EPA defines a USDW as containing less than 10,000 mg/l TDS, certain states, such as California and Texas, have adopted a producing and injection well surface pipe protection standard for fresh water aquifers that contain less than 3,000 mg/l TDS.
Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global Standards
Underground Source of Drinking Water (USDW)
“Underground Source of Drinking Water (USDW)” means an aquifer or its portion which:
(A) Supplies any public water system; or
(B) 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
(C) Is not an exempted aquifer.
Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. Regulations
Underground Source of Drinking Water (USDW)
“Underground source of drinking water” and “USDW” mean an aquifer or portion of an aquifer that supplies any public water system or that contains a sufficient quantity of groundwater to supply a public water system, and currently supplies drinking water for human consumption, or that contains fewer than ten thousand milligrams per liter total dissolved solids and is not an exempted aquifer.
Source: Division of Mineral Resources Management – Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. Regulations
Underground Source of Drinking Water (USDW)
“Underground source of drinking water” means an aquifer or its portion which:
(1) Supplies any public water system, or
(2) 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 ten thousand mg/L total dissolved solids, and
(3) Is not an exempted aquifer.
Source: Division of Mineral Resources Management – Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. Regulations
Underground Source of Drinking Water (USDW)
“Underground source of drinking water” means an aquifer that supplies water for human consumption or that contains ground water having a TDS concentration of 10,000 mg/l or less and that is not an exempted aquifer.
Source: Oil and Gas, New Mexico Administrative Code Title 19, Chapter 15, January 2013. Regulations
Underground Source of Drinking Water (USDW)
An aquifer or its portion which is not an exempt aquifer as defined in 40 Code of Federal Regulations §146.4 and which:
(A) supplies any public water system; or
(B) 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 milligrams per liter (mg/l) total dissolved solids.
Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. Regulations