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The Pennsylvania Code website reflects the Pennsylvania Code changes effective through 54 Pa.B. 1806 (March 30, 2024).

25 Pa. Code § 78a.1. Definitions.

§ 78a.1. Definitions.


 The following words and terms, when used in this chapter, have the following meanings, unless the context clearly indicates otherwise, or as otherwise provided in this chapter:

   ABACT—Antidegradation best available combination of technologies—The term as defined in §  102.1 (relating to definitions).

   Abandoned water well

     (i)   A water well that is no longer equipped in such a manner as to be able to draw groundwater.

     (ii)   The term includes a water well where the pump, piping or electrical components have been disconnected or removed or when its use on a regular or prescribed basis has been discontinued.

     (iii)   The term does not include a water well that is not currently used, but is equipped or otherwise properly maintained in such a manner as to be able to draw groundwater as an alternative, backup or supplemental water supply.

   Accredited laboratory—A laboratory accredited by the Department under Chapter 252 (relating to environmental laboratory accreditation).

   Act—58 Pa.C.S. § §  3201—3274 (relating to development).

   Act 2—The Land Recycling and Environmental Remediation Standards Act (35 P.S. § §  6026.101—6026.908).

   Anti-icing—Brine applied directly to a paved road prior to a precipitation event.

   Approximate original conditions—Reclamation of the land affected to preconstruction contours so that it closely resembles the general surface configuration of the land prior to construction activities and blends into and complements the drainage pattern of the surrounding terrain, and can support the land uses that existed prior to the applicable oil and gas operations to the extent practicable.

   Attainable bottom—The depth, approved by the Department, which can be achieved after a reasonable effort is expended to clean out to the total depth.

   Barrel—A unit of volume equal to 42 US liquid gallons.

   Body of water—The term as defined in §  105.1 (relating to definitions).

   Borrow pit—An area of earth disturbance activity where rock, stone, gravel, sand, soil or similar material is excavated for construction of well sites, access roads or facilities that are related to oil and gas development.

   Building—An occupied structure with walls and roof within which persons live or customarily work.

   Casing seat—The depth to which casing is set.

   Cement—A mixture of materials for bonding or sealing that attains a 7-day maximum permeability of 0.01 millidarcies and a 24-hour compressive strength of at least 500 psi in accordance with applicable standards and specifications.

   Cement job log—A written record that documents the actual procedures and specifications of the cementing operation.

   Centralized impoundment—A facility authorized by a Permit for a Centralized Impoundment Dam for Oil and Gas Operations (DEP # 8000-PM-OOGM0084).

   Certified mail—Any verifiable means of paper document delivery that confirms the receipt of the document by the intended recipient or the attempt to deliver the document to the proper address for the intended recipient.

   Coal area—An area that is underlain by a workable coal seam.

   Coal protective casing—A string of pipe which is installed in the well for the purpose of coal segregation and protection. In some instances the coal protective casing and the surface casing may be the same.

   Common areas of a school’s property—An area on a school’s property accessible to the general public for recreational purposes. For the purposes of this definition, a school is a facility providing elementary, secondary or postsecondary educational services.

   Condensate—A low-density, high-API gravity liquid hydrocarbon phase that generally occurs in association with natural gas. For the purposes of this definition, high-API gravity is a specific gravity scale developed by the American Petroleum Institute for measuring the relative density of various petroleum liquids, expressed in degrees.

   Conductor pipe—A short string of large-diameter casing used to stabilize the top of the wellbore in shallow unconsolidated formations.

   Deepest fresh groundwater—The deepest fresh groundwater bearing formation penetrated by the wellbore as determined from drillers logs from the well or from other wells in the area surrounding the well or from historical records of the normal surface casing seat depths in the area surrounding the well, whichever is deeper.

   De-icing—Brine applied to a paved road after a precipitation event.

   Drill cuttings—Rock cuttings and related mineral residues generated during the drilling of an oil or gas well.

   Floodplain—The area inundated by the 100-year flood as identified on maps and flood insurance studies provided by the Federal Emergency Management Agency, or in the absence of these maps or studies or any evidence to the contrary, the area within 100 feet measured horizontally from the top of the bank of a perennial stream or 50 feet from the top of the bank of an intermittent stream.

   Freeboard—The vertical distance between the surface of an impounded or contained fluid and the lowest point or opening on a lined pit edge or open top storage structure.

   Fresh groundwater—Water in that portion of the generally recognized hydrologic cycle which occupies the pore spaces and fractures of saturated subsurface materials.

   Gas storage field—A gas storage reservoir and all of the gas storage wells connected to the gas storage reservoir.

   Gas storage reservoir—The portion of a subsurface geologic formation or rock strata used for or being tested for storage of natural gas that:

     (i)   Has sufficient porosity and permeability to allow gas to be injected or withdrawn, or both.

     (ii)   Is bounded by strata of insufficient porosity or permeability, or both, to allow gas movement out of the reservoir.

     (iii)   Contains or will contain injected gas geologically or by pressure control.

   Gas storage well—A well located and used in a gas storage reservoir for injection or withdrawal purposes, or an observation well.

   Gathering pipeline—A pipeline that transports oil, liquid hydrocarbons or natural gas from individual wells to an intrastate transmission pipeline regulated by the Pennsylvania Public Utility Commission or interstate transmission pipeline regulated by the Federal Energy Regulatory Commission.

   Gel—A slurry of clay or other equivalent material and water at a ratio of not more than seven barrels of water to each 100 pounds of clay or other equivalent matter.

   Inactive well—A well granted inactive status by the Department under section 3214 of the act (relating to inactive status) and §  78a.101 (relating to general provisions).

   Intermediate casing—A string of casing set after the surface casing and before production casing, not to include coal protection casing, that is used in the wellbore to isolate, stabilize or provide well control.

   L.E.L.—Lower explosive limit.

   Limit of disturbance—The boundary within which it is anticipated that earth disturbance activities (including installation of best management practices) will take place.

   Mine influenced water—Any of the following:

     (i)   Water in a mine pool.

     (ii)   Surface discharge of water caused by mining activities that pollutes or may create a threat of pollution to waters of the Commonwealth.

     (iii)   A surface water polluted by mine pool water.

     (iv)   A surface discharge caused by mining activities.

   Modular aboveground storage structure—An aboveground structure used to store wastewater that requires final assembly at a well site to function and which can be disassembled and moved to another well site after use.

   Noncementing material—A mixture of very fine to coarse grained nonbonding materials, including unwashed crushed rock, drill cuttings, earthen mud or other equivalent material approved by the Department.

   Noncoal area—An area that is not underlain by a workable coal seam.

   Nonporous material—Nontoxic earthen mud, drill cuttings, fire clay, gel, cement or equivalent materials approved by the Department that will equally retard the movement of fluids.

   Observation well—A well used to monitor the operational integrity and conditions in a gas storage reservoir, the reservoir protective area, or strata above or below the gas storage horizon.

   Oil and gas operations—The term includes the following:

     (i)   Well site preparation, construction, drilling, hydraulic fracturing, completion, production, operation, alteration, plugging and site restoration associated with an oil or gas well.

     (ii)   Water withdrawals, residual waste processing, water and other fluid management and storage used exclusively for the development of oil and gas wells.

     (iii)   Construction, installation, use, maintenance and repair of:

       (A)   Oil and gas well development, gathering and transmission pipelines.

       (B)   Natural gas compressor stations.

       (C)   Natural gas processing plants or facilities performing equivalent functions.

     (iv)   Construction, installation, use, maintenance and repair of all equipment directly associated with activities in subparagraphs (i)—(iii) to the extent that the equipment is necessarily located at or immediately adjacent to a well site, impoundment area, oil and gas pipeline, natural gas compressor station or natural gas processing plant.

     (v)   Earth disturbance associated with oil and gas exploration, production, processing, or treatment operations or transmission facilities.

   Other critical communities

     (i)   Species of special concern identified on a PNDI receipt, including plant or animal species:

       (A)   In a proposed status categorized as proposed endangered, proposed threatened, proposed rare or candidate.

       (B)   That are classified as rare or tentatively undetermined.

     (ii)   The term does not include threatened and endangered species.


     (i)   A person who owns, manages, leases, controls or possesses a well or coal property.

     (ii)   The term does not apply to orphan wells, except when the Department determines a prior owner or operator benefited from the well as provided in section 3220(a) of the act (relating to plugging requirements).

   PCSM—Post-construction stormwater management—The term as defined in §  102.1.

   PCSM plan—The term as defined in §  102.1.

   PNDI—Pennsylvania Natural Diversity Inventory—The Pennsylvania Natural Heritage Program’s database containing data identifying and describing this Commonwealth’s ecological information, including plant and animal species classified as threatened and endangered as well as other critical communities provided by the Department of Conservation and Natural Resources, the Fish and Boat Commission, the Game Commission and the United States Fish and Wildlife Service. The database informs the online environmental review tool. The database contains only those known occurrences of threatened and endangered species and other critical communities, and is a component of the Pennsylvania Conservation Explorer.

   PNDI receipt—The results generated by the Pennsylvania Natural Diversity Inventory Environmental Review Tool containing information regarding threatened and endangered species and other critical communities.

   PPC plan—Preparedness, Prevention and Contingency plan—A written preparedness, prevention and contingency plan.

   Perimeter area—An area that begins at the outside coal boundaries of an operating coal mine and extends within 1,000 feet beyond those boundaries or an area within 1,000 feet beyond the mine permit boundaries of a coal mine already projected and permitted but not yet being operated.

   Permanently cemented—Surface casing or coal protective casing that is cemented until cement is circulated to the surface or is cemented with a calculated volume of cement necessary to fill the theoretical annular space plus 20% excess.

   Pit—A natural topographic depression, manmade excavation or diked area formed primarily of earthen materials designed to hold fluids, semifluids or solids.


     (i)   An outdoor area provided to the general public for recreational purposes.

     (ii)   The term includes community-operated recreational facilities.

   Pre-wetting—Mixing brine with antiskid material prior to roadway application.

   Primary containment—A pit, tank, vessel, modular aboveground storage structure, temporary storage facility or other equipment designed to hold regulated substances including all piping and other appurtenant facilities located on the well site.

   Private water supply—A water supply that is not a public water supply.

   Process or processing—The term has the same meaning as ‘‘processing’’ as defined in section 103 of the Solid Waste Management Act (35 P.S. §  6018.103).

   Production casing—A string of pipe other than surface casing and coal protective casing which is run for the purpose of confining or conducting hydrocarbons and associated fluids from one or more producing horizons to the surface.

   Public resource agency—An entity responsible for managing a public resource identified in §  78a.15(d) or (f)(1) (relating to application requirements) including the Department of Conservation and Natural Resources, the Fish and Boat Commission, the Game Commission, the United States Fish and Wildlife Service, the United States National Park Service, the United States Army Corps of Engineers, the United States Forest Service, counties, municipalities and playground owners.

   Public water supply—A source of water used by a water purveyor.

   Regional groundwater table

     (i)   The fluctuating upper water level surface of an unconfined or confined aquifer where the hydrostatic pressure is equal to the ambient atmospheric pressure.

     (ii)   The term does not include the perched water table or the seasonal high groundwater table.

   Regulated substance—The term as defined in section 103 of Act 2 (35 P.S. §  6026.103).

   Residual waste—The term as defined in §  287.1 (relating to definitions).

   Retrievable—When used in conjunction with surface casing, coal protective casing or production casing, the casing that can be removed after exerting a prudent effort to pull the casing while applying a pulling force at least equal to the casing weight plus 5,000 pounds or 120% of the casing weight, whichever is greater.

   Seasonal high groundwater table—The saturated condition in the soil profile during certain periods of the year. The condition can be caused by a slowly permeable layer within the soil profile and is commonly indicated by the presence of soil mottling.

   Secondary containment—A physical barrier specifically designed to minimize releases into the environment of regulated substances from primary containment or well development pipelines, to prevent comingling of incompatible released regulated substances and to minimize the area of potential contamination, to the extent practicable.

   Sheen—An iridescent appearance on the surface of the water.

   Soil mottling—Irregular marked spots in the soil profile that vary in color, size and number.

   Stormwater—Runoff from precipitation, snowmelt, surface runoff and drainage.

   Surface casing—A string or strings of casing used to isolate the wellbore from fresh groundwater and to prevent the escape or migration of gas, oil or other fluids from the wellbore into fresh groundwater. The surface casing is also commonly referred to as the water string or water casing.

   Threatened or endangered species—Those animal and plant species identified as a threatened or endangered species as determined under the Endangered Species Act of 1973 (16 U.S.C.A. § §  1531—1544), the Wild Resource Conservation Act (32 P.S. § §  5301—5314), 30 Pa.C.S. (relating to Fish and Boat Code) and 34 Pa.C.S. (relating to Game and Wildlife Code).

   Tophole water—Water that is brought to the surface while drilling through the strata containing fresh groundwater and water that is fresh groundwater or water that is from a body of surface water. Tophole water may contain drill cuttings typical of the formation being penetrated but may not be polluted or contaminated by additives, brine, oil or man-induced conditions.

   Total depth—The depth to which the well was originally drilled, subsequently drilled or the depth to which it was plugged back in a manner approved by the Department.

   Tour—A workshift in drilling of a well.

   Unconventional formation—A geological shale formation existing below the base of the Elk Sandstone or its geologic equivalent stratigraphic interval where natural gas generally cannot be produced at economic flow rates or in economic volumes except by vertical or horizontal well bores stimulated by hydraulic fracture treatments or by using multilateral well bores or other techniques to expose more of the formation to the well bore.

   Unconventional well or well—A bore hole drilled or being drilled for the purpose of or to be used for the production of natural gas from an unconventional formation.

   WMP—Water management plan—A plan associated with drilling or completing a well in an unconventional formation that demonstrates that the withdrawal and use of water sources within this Commonwealth protects those sources, as required under law, and protects public health, safety and welfare.

   Water protection depth—The depth to a point 50 feet below the surface casing seat.

   Water purveyor—Either of the following:

     (i)   The owner or operator of a public water system as defined in section 3 of the Pennsylvania Safe Drinking Water Act (35 P.S. §  721.3).

     (ii)   Any person subject to the act of June 24, 1939 (P.L. 842, No. 365) (32 P.S. § §  631—641), known as the Water Rights Law.

   Water source

     (i)   Any of the following:

       (A)   Waters of the Commonwealth.

       (B)   A source of water supply used by a water purveyor.

       (C)   Mine pools and discharges.

       (D)   Any other waters that are used for drilling or completing a well in an unconventional formation.

     (ii)   The term does not include flowback or production waters or other fluids:

       (A)   Which are used for drilling or completing a well in an unconventional formation.

       (B)   Which do not discharge into waters of the Commonwealth.

   Water supply—A supply of water for human consumption or use, or for agricultural, commercial, industrial or other legitimate beneficial uses.

   Watercourse—The term as defined in §  105.1.

   Waters of the Commonwealth—The term as defined in section 1 of The Clean Streams Law (35 P.S. §  691.1).

   Well development impoundment—A facility that is:

     (i)   Not regulated under §  105.3 (relating to scope).

     (ii)   A natural topographic depression, manmade excavation or diked area formed primarily of earthen materials although lined with synthetic materials.

     (iii)   Designed to hold surface water, fresh groundwater and other fluids approved by the Department.

     (iv)   Constructed for the purpose of servicing multiple well sites.

   Well development pipelines—Pipelines used for oil and gas operations that:

     (i)   Transport materials used for the drilling or hydraulic fracture stimulation, or both, of a well and the residual waste generated as a result of the activities; and,

     (ii)   Lose functionality after the well site it serviced has been restored under §  78a.65 (relating to site restoration).

   Well operator or operator—Any of the following:

     (i)   The person designated as the operator or well operator on the permit application or well registration.

     (ii)   If a permit or registration was not issued, a person who locates, drills, operates, alters or plugs a well or reconditions a well with the purpose of production from the well.

     (iii)   If a well is used in connection with the underground storage of gas, a storage operator.

   Well site—The area occupied by the equipment or facilities necessary for or incidental to the drilling, production or plugging of a well.

   Wellhead protection area—The term as defined in §  109.1 (relating to definitions).

   Wetland—The term as defined in §  105.1.

   Workable coal seam—Either of the following:

     (i)   A coal seam in fact being mined in the area in question under the act and this chapter by underground methods.

     (ii)   A coal seam which, in the judgment of the Department, reasonably can be expected to be mined by underground methods.


   The provisions of this §  78a.1 amended under 58 Pa.C.S. §  3211(d) and 3274; and section 1920-A of The Administrative Code of 1929 (71 P.S. §  510-20).


   The provisions of this §  78a.1 corrected October 28, 2016, effective October 8, 2016, 46 Pa.B. 6829; amended July 31, 2020, effective August 1, 2020, 50 Pa.B. 3845. Immediately preceding text appears at serial pages (383851) to (383859).

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