North Dakota Administrative Code › Title 33.1 - Department of Environmental Quality › Article 33.1-18 - Water Well Contractors › Chapter 33.1-18-01 - Water Well Construction and Water Well Pump Installation › Section 33.1-18-01-05 - Protection of ground water sources

Current through Supplement No. 393, July, 2024
1.
Minimum
				protective depths of wells.
All wells shall be watertight to exclude
				contamination. Wells shall be designed to seal off formations that are or may
				be contaminated or undesirable.
Unless approved otherwise by the department, the annular
				  space between a well hole excavation and the outside of the well casing shall
				  be filled with neat cement grout, high-solids bentonite clay grout, bentonite
				  chips, or bentonite tablets at least one and one-half inches [3.81 centimeters]
				  in thickness from a depth of not less than thirty feet [9.1 meters] to the
				  ground surface or the upper end of the well casing if a pitless unit or adapter
				  is installed. Wells with a depth of thirty feet [9.1 meters] or less shall be
				  grouted from within two feet [60.96 centimeters] of the top of the well screen
				  to the ground surface or the upper end of the well casing if a pitless unit or
				  adapter is installed. Greater depths are preferable and may be required for
				  specific installations as determined by review of the plans and
				  specifications.
The annular space of wells constructed in unconsolidated
				  formations without overlying confining beds and static water levels less than
				  thirty feet [9.1 meters] below the ground surface shall be filled with neat
				  cement grout, high-solids bentonite clay grout, bentonite chips, or bentonite
				  tablets at least one and one-half inches [3.81 centimeters] in thickness from
				  the static water level or a depth of not less than ten feet [3.0 meters],
				  whichever is greater, to the ground surface or the upper end of the well casing
				  if a pitless unit or adapter is installed.
Driven well casing may, when conditions warrant, be installed
				  without grouting.
2.
Required
				protection for various sources.
a.
				Radial collector wells. The location of all caisson construction joints and
				porthole assemblies shall be indicated. The caisson wall shall be substantially
				reinforced. Radial collectors shall be in areas and at depths approved by the
				department. Provisions shall be made to assure minimum vertical rise. The top
				of the caisson shall be covered with a watertight floor. All openings in the
				floor shall be curbed and protected from entrance of foreign material. Pump
				discharge piping shall not be placed through caisson walls.
b. Dug or bored wells. Dug or bored wells
				greater than two feet [60.96 centimeters] in diameter shall be developed only
				where geological conditions preclude the development of a satisfactory drilled
				well.
Every dug or bored well shall have a continuous watertight
				  casing. The section of casing in the producing zone serving as the well screen
				  shall readily admit water and be structurally sound to withstand external
				  pressures.
The open space between the excavation and the installed
				  casing shall be sealed with neat cement grout, high-solids bentonite clay
				  grout, bentonite chips, or bentonite tablets.
The watertight casing shall extend at least twelve inches
				  [30.48 centimeters] above finished ground surface. A cover slab at least four
				  inches [10.16 centimeters] thick, adequately reinforced and having a diameter
				  sufficient to overlap the lining by two inches [5.08 centimeters] shall be
				  provided. The slab shall be constructed without joints.
The top of the slab shall be sloped to drain to all sides
				  and a watertight joint made where the slab rests on the well casing using
				  cement mortar or a mastic compound.
A manhole, if installed, shall be provided with a curb cast
				  in the slab and extending at least four to six inches [10.16 to 15.24
				  centimeters] above the slab. The manhole shall have a watertight overlapping
				  cover extending down around the curb by at least two inches [5.08
				  centimeters].
Adequate sized pipe sleeve or sleeves shall be cast in place
				  in the slab to accommodate the type of pump or pump piping proposed for the
				  well.
c. Infiltration wells.
				Infiltration wells may be considered where geological conditions preclude
				possibility of developing an acceptable drilled well. The area around the well
				shall be under the control of the water purveyor for a distance acceptable to
				or required by the department. The flow in the lines shall be by gravity to a
				collecting well. The water shall be continuously chlorinated to assure
				bacterial purity.
d. Flowing wells.
				The construction of flowing wells shall be in compliance with North Dakota
				Century Code chapter 61-20.
The construction of flowing wells shall be such that the
				  flow from them can be controlled. Well casing shall be installed, and the
				  annular space grouted with neat cement to form a tight seal. The neat cement
				  grout shall extend upward from within twenty feet [6.1 meters] of the top of
				  the aquifer to the ground surface or the upper end of the well casing if a
				  pitless unit or adapter is installed.
Well casings shall be joined in a watertight manner. Flow
				  control should consist of valved pipe connections, watertight pump connections,
				  or receiving reservoirs set at an elevation corresponding to the artesian
				  head.
e. Existing wells. The
				department shall be consulted for requirements concerning the reconstruction of
				existing wells.