Terminology

Well Terminology

Printable terminology (pdf)

A.A.C.

Abbreviation for Arizona Administrative Code.

A.R.S.

Abbreviation for Arizona Revised Statutes.

Abandonment

Well abandonment is accomplished “through filling or sealing the well so as to prevent the well, including the annular space outside the casing, from being a channel allowing the vertical movement of water.” A.A.C. R12-15-816(G). Wells that are capped and not in use are not considered abandoned.

Acre-foot

A unit of volume equal to the amount of water it would take to cover an acre of land with a sheet of water one foot deep. Equal to 43,560 cubic feet, or 325,851 gallons of water. 

Active Management Area (AMA)

This is a geographical area which has been designated pursuant to [A.R.S. Title 45, Chapter 2, Article 2] as requiring active management of groundwater or, in the case of the Santa Cruz Active Management Area, active management of any water, other than stored water, withdrawn from a well. A.R.S. § 45-402(2). Established Active Management Areas (AMAs) include: The Phoenix, Pinal, Prescott, Tucson, and Santa Cruz AMAs. A map of the AMAs and their boundaries can be viewed here. Wells drilled in AMAs are subject to stricter regulations. 

Annular space

The space between the outer well casing and the borehole wall. Also means the space between the inner and outer well casing. A.A.C. R12-15-801(1).

Artesian aquifer

An aquifer which is overlain by a confining formation and which contains groundwater under sufficient pressure for the water to rise above the top of the aquifer. A.A.C. R12-15-801(3).

Artesian well

A well that penetrates an artesian aquifer. A.A.C. R12-15-801(4).

aquifer

An underground formation capable of yielding or transmitting usable quantities of water. A.A.C. R12-15-801(2).

bentonite

A colloidal clay composed mainly of sodium montmorillonite, a hydrated aluminum silicate. A.A.C. R12-15-801(5).

cadastral

(Pronounced “Ka-Dah-Strel”). This refers to a rectangular coordinate system that is used to map much of Arizona. Arizona is divided into four unequal quadrants (A, B, C, D), with a north-south line called meridian and an east-west line called baseline. The northeast quadrant is “A”, the northwest “B”, the southwest “C”, and the southeast “D”.

From here, each quadrant is subdivided into Townships (capital “T”). Each Township is defined by a township (lowercase “T”) north or south of baseline and a range east or west of meridian.

Regularly sized Townships consist of 36 sections. Each section in a regularly sized Township is 1 square mile, or 640 acres in size. Each 640-acre section is then divided into four 160-acre quarters. Each 160-acre quarter is then subdivided into four 40-acre quarters, and each 40-acre quarter is subdivided into four 10-acre quarters.

On our wells 55 map, wells are plotted to the nearest 10-acre quarter or section, rather than the exact, physical location. For more information regarding the cadastral system, please view this pamphlet.

cap

A tamper-resistant, watertight steel plate of at least one-quarter inch thickness on the top of all inside and outside casings of a well. A.A.C. R12-15-801(6).

CAsing

The tubing or pipe installed in the borehole during or after drilling to support the sides of the well and prevent caving. A.A.C. R12-15-801(7).

confining formation

The relatively impermeable geologic unity immediately overlying an artesian aquifer. A.A.C. R12-15-801(8).

COmprehensive environmental response, compensation, and liability act of 1980 (ceRcla) site

This is a location included in the federal government’s "Superfund" program, which investigates sites that are contaminated with hazardous substances. The Superfund program develops remedial actions that assure the protection of public health and welfare and the environment. The CERCLA program is administered by the United States Environmental Protection Agency (USEPA). The CERCLA Act of 1980 is authorized by P.L. 96-510; 94 Stat. 2767; 42 United States Code §§ 9601 through 9657. A.R.S. § 49-201(4).

Community water system

Community water systems are any system that serves 15 or more service connections, or which serves 25 or more residents, on a year-round basis. They are subject to water quality standards and more stringent reporting requirements A.R.S. §§ 45-341 to 343. Community water systems are also regulated by the Arizona Department of Environmental Quality.

contaminated groundwater

Groundwater that has been contaminated by a release of a hazardous substance, as defined in section 49-201, or a pollutant, as defined in section 49-201. A.R.S. § 45-596(H1).

consolidated formation

A naturally occurring geologic unit through or into which a well is drilled, having a composition, density, and thickness which will provide a natural hydrologic barrier. A.A.C. R12-15-801(8).

County or local health authority approval

If water from the proposed well, or existing well being modified or deepened, will be used for domestic purposes on a parcel of land of 5 or fewer acres, the applicable county or local health authority must endorse all items in Section 1 on the Notice of Intent (NOI) to Drill within one year before submission to the Department of Water Resources. A site plan must also be attached. A.R.S. § 45-596(F). 

Department of defense (DOD) site

This is a location that is contaminated with hazardous substances. These locations typically are either active duty military bases or bases being closed under the Base Realignment and Closure (BRAC) regulations, as well as formerly used defense sites that are eligible for funding under the Installation Restoration Program as overseen by Arizona Department of Environmental Quality (ADEQ). DOD sites are administered by the US military and are authorized by the Defense Environmental Restoration Program, U.S.C. § 2701, et seq.

Domestic well

This is a small capacity water-production well that is used to provide water for domestic purposes. Domestic purposes are defined as uses related to the supply, service and activities of households and private residences. This includes the application of water to less than two acres of land to produce plants or parts of plants for sale or human consumption, or for use as feed for livestock, range livestock or poultry as such terms are defined in § 3-1201. A.R.S. § 45-454(M1). For information regarding drilling a domestic well, please read A Practical Guide to Drilling a Domestic Water Well in Arizona. 

drill card

A card which is used by the Department to the well drilling contractor or single well licensee designated in the notice of intent or permit, authorizing the well drilling contractor or licensee to drill the specific well or wells in the specific location as noticed or permitted. A.A.C. R12-15-801(12).

Environmental well

This is a type of well normally associated with a site investigation or remedial action. Environmental wells include air-sparging wells, biosparging wells, vapor extraction wells, free product recovery wells, vadose zone wells and wells involving other types of remediation. Environmental wells are permanent installations, as opposed to geotechnical or exploration boreholes that are drilled to obtain samples or information, and then are immediately abandoned.

Exempt well

This is a well having a pump with a maximum capacity of not more than thirty-five gallons per minute which is used to withdraw groundwater pursuant to A.R.S. § 45-454. A.R.S. § 45-402(8).

Exempt wells are small non-irrigation wells, typically used to provide water for domestic purposes. In AMAs, withdrawals of groundwater from exempt wells for non-irrigation uses other than domestic purposes and stock watering shall not exceed 10 acre-feet per year. A.R.S. § 45-454(B2).

EXisting well

A well which was drilled before June 12, 1980 and which is not abandoned or sealed or a well which was not completed on June 12, 1980 but for which a Notice of Intent to Drill was on file with the Arizona Water Commission on such date. A.R.S. § 45-591(1).

EXploration well

This is a well drilled in search of geophysical, mineralogical or geotechnical data. A.A.C. R12-15-801(13).

Flowing artesian well

An artesian well in which the pressure is sufficient to cause the water to rise above the land surface. A.A.C. R12-15-801(14).

groundwater basin

An area which, as nearly as known facts permit as determined by the director pursuant to this chapter, may be designated so as to enclose a relatively hydrologically distinct body or related bodies of groundwater, which shall be described horizontally by surface description. A.R.S. § 45-402(13). 

GROUNDWATER pumping outside amas and inas

Groundwater withdrawn from outside AMA and INA boundaries can be restricted in terms of its transportation between groundwater basins but is generally subject only to the requirement “for reasonable and beneficial use.” A.R.S. § 45-453. Community water systems outside of AMAs and INAs have the additional requirement to submit annual water use reports to ADWR.

The Arizona State Supreme Court has ruled that landowners do not own the groundwater beneath their property, but rather have the right to withdraw those waters. The Court stated in Town of Chino Valley vs City of Prescott, “In the absolute sense, there can be no ownership in seeping and percolating waters until they are reduced to actual possession and control by the person claiming them because of their migratory character. Like wild animals free to roam as they please, they are the property of no one.”

Outside of the AMAs and INAs, ADWR has no statutory authority to regulate the impact of one landowner’s pumping on their neighbor’s unless groundwater is being transferred between basins or sub-basins.  ADWR can investigate and inspect wells to ensure that they are properly constructed and that the associated well records are accurate A.R.S. § 45-633(A).

GROUNDWATER withdrawal authority/right

Non-exempt wells drilled within any of the five AMAs require a groundwater withdrawal authority to be issued a drill card. Some examples of a groundwater withdrawal authority include:

  • Service Area Right

    • Ex: City of Phoenix, City of Tucson, City of Prescott

  • Irrigation Grandfathered Right

    • Used for irrigation. The right to be irrigated stays with the land, rather than with the owner. 

  • Non-Irrigation Grandfathered Right

    • Type 1: Used for non-irrigation. Examples include dairy farms and golf courses. This right stays with the land.

    • Type 2: This right is the same as a Type 1, but it stays with the owner. It can be used anywhere in the AMA it was issued and can also be bought and sold. There are a limited number of Type 2 Rights.

  • General Industrial Use Permit

Groundwater rights can be viewed using this map. For more information about Groundwater Withdrawal Authorities please contact the AMA section at 602-771-8585.

GROUNDWATER WITHDRAWAL permit

This is a permit issued to withdraw groundwater in an AMA for a specific use that is authorized under A.R.S. Title 45, Chapter 2, Article 7. Authorized groundwater uses that require groundwater withdrawal permits include dewatering, temporary dewatering, emergency temporary dewatering, mineral extraction and metallurgical processing, general industrial use, poor quality groundwater, drainage water withdrawal, temporary electrical generation and hydrologic testing.

Upon receipt of an application to drill a new non-exempt well within an AMA, a hydrologic study (impact analysis) will be conducted by hydrology staff to confirm it meets well spacing and well impact rules pursuant to A.R.S. § 45-598(A).

GROut/cement grout

Cement mixed with no more than 50% sand by volume and containing no more than six gallons of water per 94 lb. sack of cement. A.A.C. R12-15-801(15).

irrigation

To apply water to two or more acres of land to produce plants or parts of plants for sale or human consumption, or as feed for livestock, range livestock, or poultry. A.R.S. § 45-402(23).

Irrigation non-expansion area (INA)

This is a geographical area which has been designated pursuant to [A.R.S. Title 45, Chapter 2, Article 3] as having insufficient groundwater to provide a reasonable safe supply for the irrigation of the cultivated lands at the current rate of withdrawal.

Established INAs include: The Joseph City, Harquahala, and Douglas INAs. A map of the INAs and their boundaries can be viewed here.

In an INA, only land that has an irrigation authority can be irrigated. Irrigation authorities can be viewed using this map.

monitor well

This is a well that is designed and drilled for the purpose of monitoring water quality within a specific depth interval. A.A.C. R12-15-801(17).

Municipal provider

This is a city, town, private water company or irrigation district that supplies water for non-irrigation use. A.R.S. § 45-454(M2). 

New well

A well for which a Notice of Intent to Drill or a permit is required pursuant to this article or which is drilled pursuant to a permit issued under section 45-834.01. A.R.S. § 45-591(2). 

Non-Exempt Well

This is any well, including a recovery well, that does not qualify as an exempt well or a replacement well. A.R.S. § 45-2701(3). A non-exempt well is a well having a pump with a maximum capacity of more than thirty-five gallons per minute which is used to withdraw groundwater. 

open well

A well which is not equipped with either a cap or a pump. A.A.C. R12-15-801(18).

Ownership of a well

ADWR maintains a registry, it does not certify legal well ownership. Wells are usually in the name of the landowner where a well resides. When the landowner or well owner changes a 55-71A Request to Change Well Information form must be filed so that the well record remains current and accurate. A.R.S. § 45-593(C). 

perforations

A series of openings in a casing, made either before or after installation of the casing, to permit the entrance of water into the well. A.A.C. R12-15-801(19).

Piezometer well

This is a well that is designed and drilled for the purpose of monitoring water levels within a specific depth interval. A.A.C. R12-15-801(20).

PItless adaptor

A commercially manufactured watertight unit or device designed for attachment to a steel well casing which permits discharge from the well below the land surface and allows access into the well casing while preventing contaminants from entering the well. A.A.C. R12-15-801(21). For more information, please view this diagram of a pitless adaptor. 

Polluted water

Water whose chemical, physical, biological, or radiological integrity has been degraded through the artificial or natural infusion of chemicals, radionuclides, heat, biological organisms, or mineralogical or other extraneous matter. A.A.C. R12-15-801(22).

Pressure grouting

A process by which a grout is confined within the borehole or casing of a well by the use of retaining plugs, packers, or a displacing fluid by which sufficient pressure is applied to drive the grout into and within the annular space or interval to be grouted. A.A.C. R12-15-801(23).

"Reasonable and beneficial use"

“Beneficial uses” includes irrigation, stock watering, industrial, mining, domestic, and many other uses.  The use of groundwater must be “reasonable” and A.R.S. 45-602 states that “Groundwater which has been withdrawn shall not be allowed to waste.”  Flowing wells must be capped if the groundwater is not being put to use, and wells, pumps, and piping must be “constructed and maintained so as to prevent the waste of groundwater.”

Registry/registration

All wells in the state, new and existing, should have a registration number beginning with “55-” followed by six digits. A.R.S. § 45-593(B). For a new well, the registration number is assigned when the Notice of Intent to Drill or Application for a Permit to Drill is received by the Department. For existing wells, the registration is assigned when the Late Registration form is received. To understand how well registration numbers are assigned, read about the Wells 55 Index Numbering System.

Shared well

A shared well may serve up to 14 service connections, or up to 24 residents in an area. Wells that serve 15 or more service connections, or which serve 25 or more residents, on a year-round basis constitute a community water system.

Well sharing agreements are private contracts executed by private parties to govern the manner in which a well provides water to multiple properties. While Arizona water law governs how a well is to be drilled and located, it does not govern the operation or management of a well sharing agreement.

Disputes regarding the terms of, or compliance with, a well sharing agreement are a purely civil matter between the parties to the agreement. Neither ADWR, or any other state agency, has authority to enforce or regulate well sharing agreements, nor may any state agency adjudicate disputes over well sharing agreements or provide legal advice to any party to a well sharing agreement.

More information on ADWR's shared well policy can be found here. 

Special Well Construction or Well Abandonment requirements

These are well construction or well abandonment requirements or standards that exceed the minimum well construction requirements provided under A.A.C. R12-15-811 and A.A.C. R12-15-816. Special well construction or abandonment requirements are required: 1) where special aquifer conditions, such as those described in A.A.C. R12-15-812, exist; 2) when it is determined that the literal application of the minimum well construction standards would not adequately protect the aquifer or other water users (A.A.C. R12-15-821); and 3) in areas of known or anticipated groundwater contamination to prevent the risk of vertical cross-contamination. A.R.S. § 45-605(E) and A.A.C. R12-15-850.

SPECIAlty Well

A specialty well is usually designed and constructed for a specific purpose other than to withdraw water, or to provide samples or monitoring data. Examples of specialty wells include cathodic protection wells, grounding wells, heat pump wells, etc.

Stock well

A well used for stock watering purposes. “Stock watering” means the watering of livestock, range livestock, or poultry, as such terms are defined in section 3-1201. A.R.S. § 45-454(M3). 

subsidence

The settling or lowering of the surface of land which results from the withdrawal of groundwater. A.R.S. § 45-402(36). Read more about land subsidence here. 

SUBstantive policy statement

This is a written expression which informs the general public of an agency’s current approach to, or opinion of, the requirements of the federal or state constitution, federal or state statute, administrative rule or regulation, or final judgment of a court of competent jurisdiction, including, where appropriate, the agency’s current practice, procedure or method of action based on that approach or opinion. A substantive policy statement is advisory only. A substantive policy statement does not include internal procedural documents which only affect the internal procedures of the agency and does not impose additional requirements or penalties on regulated parties, confidential information or rules made in accordance with this chapter. A.R.S. § 41-1001(20).

SUrface seal

ADWR well construction standards require a surface seal consisting of a minimum of 20 feet of steel casing with a 1-foot stickup. Cement grout must be used to fill the annular space between the surface casing and the borehole. There must be a minimum of 3-inch difference between the borehole diameter and the casing diameter. A.A.C. R12-15-811(B).

vadose zone well

A vadose zone well is constructed in the interval between the land surface and the top of the static water level. A.A.C. R12-15-801(26).

VAriance

A variance is a request to construct or abandon a well in a manner that does not conform to one or more provisions of A.A.C. Title 12, Chapter 15, Article 8, (rules governing the well construction and the licensing of drillers) due to extraordinary or unusual conditions. Variances must be requested in writing, or by checking applicable responses on certain types of NOI forms.

water quality

The Arizona Department of Environmental Quality (ADEQ) monitors, reports, and protects Arizona’s groundwater quality. Water quality information can be obtained from ADEQ’s Water Quality Division Website. For information regarding testing the water quality of a private well, suggested testing schedules, and labs that test water quality, visit the Arizona Department of Health Services (ADHS). 

WATER quality assurance revolving fund (wqarf) site

This is a location included in the State of Arizona’s "Superfund" program, which investigates sites that are contaminated with hazardous substances. The Superfund program develops remedial actions that assure the protection of public health and welfare and the environment. The WQARF program is administered by ADEQ. It is authorized by A.R.S. § 49-282.

Well

A man-made opening in the earth through which water may be withdrawn or obtained from beneath the surface of the earth except as provided in section 45-591.01. A.R.S. § 45-402 (43).

Wells drilled for oil, gas or helium pursuant to the provisions of title 27 are not wells as defined by this chapter. A.R.S. § 45-591.01.

WELL Drilling

The construction or repair of a well, or the modification, except for abandonment, of a well, regardless of whether compensation is involved, including any deepening or additional perforating, any addition of casing or change to existing casing construction, and any other change in well construction not normally associated with well maintenance, pump replacement, or pump repair. A.A.C. R12-15-801(29).

WELL DRILLer report and well log

A well driller report must be filed by the well driller within 30 days of the completion of a well and must describe the "as built" well construction information and provide a well log of the well. The well driller report and well log are required by A.R.S. § 45-600.

WELL DRILLing contractor

This is an individual, public or private corporation, partnership, firm, association, or any other public or private organization or enterprise that holds a well driller’s license pursuant to A.R.S. § 45-595(B). A.A.C. R12-15-801(30). A list of licensed well drillers can be found here.

WELL spacing and impact rules

These are rules that govern the location of new wells and replacement wells in new locations in Active Management Areas to prevent unreasonably increasing damage to surrounding land or other water users from the concentration of wells. Well spacing and well impact rules are authorized pursuant to A.R.S. § 45-598(A) and are set forth in A.A.C. R12-15 1301 through R12-15-1307.

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