NC Well Driller key terms

The pipe installed in a borehole to keep the hole open, prevent collapse, and stop shallow water or soil from entering the well. It must meet material and wall-thickness standards set in the NC well rules.

The gap between the borehole wall and the outside of the casing. In NC wells it must be sealed with grout to prevent surface water and shallow groundwater from moving down along the casing.

A cement-based or bentonite material placed in the annular space to form a watertight barrier. It stops contamination from following the casing downward and must be installed by an approved method such as tremie or pump placement.

A mixture of portland cement and water with no sand or aggregate, used to seal the annular space. It is the standard grout in NC rules and must be mixed and placed according to specified proportions and methods.

A clay-based slurry used to seal annular space, usually where cement grout could damage formations or where rules allow it. It must be high-solids and placed so it does not bridge or dilute in the hole.

A pipe lowered to the bottom of the annular space to place grout from the bottom up. It keeps the grout from free-falling, segregating, or bridging, and is the usual approved method for sealing casing in NC wells.

A watertight seal at the top of the well between the casing and the pump piping or well cap. It keeps surface water, insects, and debris out of the well and is required on NC wells.

A cover on top of the well casing that keeps out rain, insects, and animals while allowing access for service. It must be secured and, where required, vented and fitted with a sanitary seal.

A slotted or perforated section at the bottom of the casing that lets water in while holding back sand and gravel. Screen size and slot opening are chosen to match the formation being developed.

Filter material placed around a well screen to keep fine formation sand out of the well. It is sized to the formation and screen slot and is common in high-yield or sandy NC aquifers.

The water level in a well when the pump has been off long enough for the water to stabilize. It is measured from a fixed reference point and recorded on the well log.

The water level in a well while the pump is running at a steady rate. The difference between it and the static level shows drawdown and helps set pump depth.

The drop in water level caused by pumping, equal to the static level minus the pumping level. Too much drawdown can expose the pump intake or reduce yield.

The rate at which a well can produce water, usually stated in gallons per minute. It is measured by a pumping test and helps size the pump and decide whether the well is adequate.

A controlled test in which a well is pumped at a known rate while water levels are measured. It shows yield, drawdown, and how the aquifer responds before a pump is selected.

The process of removing drilling mud, cuttings, and fine sediment from a new well so water flows freely. Methods include surging, jetting, bailing, and pumping until the water runs clear.

The minimum required distance between a well and a potential contamination source, such as a septic system, animal lot, or property line. NC rules set specific distances that vary by feature.

The chosen spot for a new well, based on setbacks, drainage, slope, access, and the risk of flooding or contamination. It must be approved before drilling and shown on the permit application.

Land that is prone to flooding. NC rules restrict or require special construction for wells in flood-prone areas so that floodwater cannot enter the wellhead.

The written authorization issued by the local health department before a well is constructed. It lists approved location, depth, and construction requirements and must be available on site.

The record of a well's construction, including depth, casing, grout, screen, and water-bearing zones. In NC it is filed with the state and local health department after completion.

The permanent closure of a well that is no longer used. It requires filling and sealing the borehole so it cannot act as a pathway for contamination into groundwater.

The grout or other approved material placed in an abandoned well to seal it from bottom to top. It must block water movement between aquifers and prevent surface water from entering.

The technique used to make a borehole, such as rotary, air rotary, cable tool, or hollow-stem auger. The method affects sample quality, casing decisions, and how the well is developed.

A drilling method that uses compressed air to drive a bit and lift cuttings. It is fast in hard rock but can be unsuitable where air may blow contamination into the formation.

A drilling method that circulates drilling fluid to cool the bit and carry cuttings to the surface. The mud also stabilizes the hole but must be removed by development before the well is used.

A drilling method that breaks rock by repeatedly lifting and dropping a heavy bit on a cable. It gives clean samples and works well in unconsolidated formations but is slower than rotary methods.

A pump installed below the water level inside the well casing. It pushes water to the surface and must be placed deep enough to stay submerged during drawdown.

A shallow-well pump that uses a venturi nozzle to move water. It is common for shallow wells and low-yield systems but is limited by suction lift and depth.

A tank that stores water under pressure so the pump does not cycle on and off with every faucet use. It holds a captive air charge and is set to match the pump's pressure switch.

A device that turns the pump on at a low-pressure set point and off at a high-pressure set point. Correct settings protect the pump and keep household water pressure steady.

A device or air gap that stops water from flowing backward from a building or chemical system into the well. It protects the well and groundwater from contamination.

The credential issued by the NC Well Contractors Certification Commission that allows a person to construct, repair, or abandon wells. It requires qualifying experience and passing an exam.

Required training hours a licensed well contractor must complete each renewal period. It keeps licensees current on rule changes, construction methods, and safety.

The notification a contractor must file before starting certain well work, allowing the health department to inspect and track the project. It is separate from the construction permit itself.

A review of the land uses and contamination risks near a well or water source. It helps identify nearby hazards that affect where a well can be sited and how it must be constructed.