OH Well Driller key terms

A credential issued by the Ohio Department of Natural Resources authorizing a person to construct, alter, or abandon water wells in Ohio. It is issued by class of well and requires renewal.

A category of driller license tied to a specific type of well or drilling method, such as water well, monitoring well, or geotechnical hole, each with its own scope of authorized work.

The number of approved training hours a licensed driller must complete during each renewal cycle to maintain the license in active status.

A financial assurance obligation a driller must satisfy, typically a surety bond filed with the state, to guarantee compliance with well construction and abandonment rules.

The supervisory role a licensed driller holds over drilling operations, meaning the licensee directs and is accountable for the work performed at the site.

A well installed primarily to observe groundwater levels or collect samples for water quality analysis rather than to supply drinking water, often held to specific construction standards.

A bored, drilled, driven, or dug hole that taps an aquifer for potable or other beneficial use, constructed with casing and sealed to protect groundwater.

A drilling method that rotates a bit while circulating drilling fluid to cut rock and carry cuttings to the surface, commonly used for deep or hard-rock water wells.

A rotary technique that uses compressed air instead of liquid mud to remove cuttings, useful in hard formations and where minimizing formation damage matters.

A percussion method in which a heavy bit is repeatedly lifted and dropped to break rock, with a bailer removing cuttings from the borehole.

A liquid mixture, often water with bentonite or polymers, circulated during drilling to cool the bit, carry cuttings, and stabilize the borehole wall.

A clay composed largely of montmorillonite that swells when hydrated, used in drilling mud and as a base for grout seals in well construction.

The pipe installed in a borehole to keep the hole open, prevent collapse, and isolate the well from surrounding formations and surface contamination.

The gap between the outside of the well casing and the wall of the borehole, which must be sealed to prevent water movement along the casing.

A cementitious or bentonite-based material placed in the annular space to form a low-permeability seal that blocks vertical movement of water and contaminants.

A mixture of Portland cement and water, sometimes with additives, used to seal annular spaces because of its strength and low permeability after setting.

A slotted or perforated section of pipe placed at the producing zone to admit water while holding back sand and formation material.

Sorted gravel or sand placed in the annulus around a well screen to filter formation material and improve well yield and efficiency.

The grouted or otherwise sealed connection at the top of a well that prevents surface water and contaminants from entering the annular space or wellhead.

A tight-fitting cover on the top of the casing that excludes surface water, insects, and debris while allowing access for measurement and maintenance.

The process of removing drilling mud, fines, and loose material from the formation near a well so that it produces clear water at higher efficiency.

A development technique that forces water in and out of the screen with a plunger-like tool to loosen and flush out fine material from the gravel pack and formation.

The yield of a well expressed as pumping rate divided by drawdown, used to compare well performance and detect deterioration over time.

The drop in water level in a well caused by pumping, measured as the difference between static and pumping water levels.

The level at which water stands in a well when no pumping or other disturbance is affecting it, representing ambient aquifer conditions.

A controlled test in which a well is pumped at a measured rate while water levels are recorded to determine yield, drawdown, and aquifer characteristics.

Treatment of a new or repaired well with a chlorine solution to kill bacteria and other microorganisms before the well is placed into service.

The concentration of chlorine remaining in well water after disinfection, used to confirm that adequate contact and dosing were achieved.

A water sample collected under sterile conditions and submitted to a laboratory to test for coliform bacteria and other indicators of contamination.

The permanent decommissioning of a well that is no longer used, requiring sealing of the borehole so it cannot transmit water or contaminants between aquifers.

Filling and sealing an abandoned well with approved materials such as grout or bentonite to restore the natural confining layers of the aquifer.

The record a driller files with the state describing the location, depth, materials, and method used to seal an abandoned well.

A record of the geological formations, casing, screen, and grout intervals encountered in a well, filed with the state after construction.

An authorization, where required, that must be obtained before constructing a well, confirming the proposed location and construction meet state and local requirements.

The minimum required separation between a well and potential contamination sources such as septic systems, animal lots, or property lines.

Water stored in and moving through the pores and fractures of soil and rock beneath the land surface, the resource that wells are designed to tap and protect.

A saturated geologic formation that can store and transmit enough water to supply a well at a useful rate.

The periodic reporting of volumes withdrawn from a well or facility above a threshold, used by the state to track and manage water resources.

The land surface and subsurface zone around a well or wellfield through which contaminants could reach the water supply, subject to land-use controls.