Mississippi Administrative Code › Title 11 - Mississippi Department of Environmental Quality › Part 7 - Surface Water and Groundwater Use and Protection, Licensing of Water Well Contractors and Dam Safety Regulations › Chapter 2 - Mississippi Commission on Environmental Quality Licensing of Water Well Contractors Regulations › Rule 11-7-2.12 - Design Criteria And Construction Standards

Current through June 25, 2024
The Licensee shall be responsible for compliance with all
				  applicable state and federal statutes and regulations.
A.
Water Wells and Boreholes
				Penetrating Aquifers In General Use For Domestic and Public Water
				Supply
- The standards contained herein are the minimum
				construction standards considered necessary for the protection of the states
				high-quality groundwater resources. Other regulatory programs may be applicable
				and additional standards may be required for certain types of facilities, such
				as Mississippi State Department of Health regulations governing public supply
				wells. If a water well contractor encounters geologic formations or unusual
				circumstances that appear to dictate a deviation from the standards, the
				contractor shall consult with MDEQ staff regarding proposed construction
				procedures for the water well or borehole in question.
(1)
Construction
				Standards
- The following construction standards apply to wells and
				boreholes penetrating water bearing strata including but not limited to,
				potable water wells, irrigation wells, monitoring wells, observation wells,
				underground discharge wells, dewatering wells, saline or brackish water
				withdrawal wells, contaminant recovery wells, heat pump water supply holes and
				vertical closed-loop system holes, industrial supply wells, cathodic protection
				wells, rig supply wells and geotechnical boreholes:
(a) All water wells and boreholes covered
				under this section shall be constructed by a licensed water well contractor
				unless specifically exempted by statute.
(b) Well casing shall terminate not less than
				twelve (12) inches above natural ground elevation or, where practicable, above
				the 100-year flood elevation. However, if flood levels around the well
				routinely exceed a reasonable height for an extended casing above the twelve
				(12) inch minimum, then the well shall be fully sealed with a Braden Casing
				Head, or approved equivalent, to prevent the flow of flood waters into the
				casing. The casing head shall contain a screw-in plug with a minimum diameter
				of one-half (1/2) inch to provide access for water level measurements. If the
				casing is not covered with a recorder box or pump housing, then it must have a
				locked, overlapping cover or other suitable cover capable of preventing
				unauthorized access to the casing head and access plug.
(c) Public water supply wells shall have the
				top of the well casing set at least one (1) foot above the 100-year flood
				level.
(d) All wells shall have a
				check valve installed in the discharge line to prevent the intentional or
				accidental introduction of contaminants into the well. All new unmetered wells
				larger than six (6) inches in diameter shall have a minimum of four (4) feet of
				straight pipe installed between the casing head and the check valve, and all
				other equipment, valves, pressure relief valves, vacuum breakers, and
				distribution systems shall be connected on the discharge side of the check
				valve.
(e) All wells, except
				approved underground discharge wells as specified in paragraph o. below, shall
				be constructed in such a manner that the finished ground elevations around the
				casing are sloped to drain away from the casing. Equipment such as engines,
				pressure tanks, or fuel tanks to be installed shall be placed on pre-cast
				concrete blocks or pads to prevent differential settlement that could result in
				damage to the pump and the well.
(f) The annular space on all wells covered by
				this section of the regulation shall be grouted from a depth of at least ten
				(10) feet below the surface to the surface, except as specified in paragraphs
				g, i, j, k, l, m, o, and p below.
(g) Wells located within one hundred (100)
				feet of a potential source of pollution such as sewers, septic tanks,
				landfills, and waste and raw material piles shall be grouted from a depth of at
				least fifty (50) feet below the land surface to the surface, except as
				specified in paragraphs h, i, j, k, l, n, and o below.
(h) Potable water wells shall not be
				constructed within 100 feet of any potential source of pollution.
(i) Wells located within one-quarter mile of
				a known existing area of contaminated aquifer shall be grouted from the top of
				the water bearing stratum to the ground surface, or the top of the casing for
				underground discharge wells.
(j)
				Outer casing for wells serving public water supply systems shall be grouted
				from the top of the target water bearing stratum to the ground
				surface.
(k) monitoring wells shall
				be grouted from the top of the seal or filter pack to the ground surface,
				unless a more stringent requirement is mandated by other applicable regulatory
				programs. Specifics of monitoring well construction shall follow the most
				stringent requirements of the applicable regulatory programs.
(l) Cathodic protection wells shall be
				grouted from a depth of fifty (50) feet below ground surface to the ground
				surface. Wells constructed with granular material such as gravel from the top
				of the anodes to near the surface are prohibited. If wells are no longer used,
				the vent pipe, casing or other non-grouted openings shall be grouted from a
				depth of at least ten (10) feet below the ground surface to the ground
				surface.
(m) For continuous lengths
				of grout not separated by multiple screens, grout shall be introduced in one
				continuous operation from the top of the water rearing stratum to the ground
				surface.
(n) Grout for all holes
				covered under this section shall consist of either neat cement, cement grout,
				cement-bentonite mixture (5-8[CENT] bentonite), or bentonite. Bentonite pellets
				or bentonite chips may be added under free-fall conditions for depths not
				exceeding twenty-five (25) feet. Free-fall addition of any other type grout
				from the surface is prohibited. Granulated or pelletized bentonite may be
				placed to greater depths only if introduced through a tremie pipe.
(o) All wells, regardless of size, which are
				drilled through or into aquifers containing chloride concentrations in excess
				of 250 milligrams per liter (mg/l) and/or total dissolved solids (TDS)
				concentrations in excess of 1000 milligrams per liter (mg/l), must be completed
				using metal casing. Furthermore, all such wells shall be completed using only
				the casing method of grouting (Halliburton method) to grout thoroughly the
				annular space from the bottom of the casing to ground surface or to the top of
				the casing for underground discharge wells.
(p) Outer casing for underground discharge
				domestic wells shall be grouted from a depth of at least ten (10) feet below
				the top of the casing at the underground discharge head, or pitless adapter, to
				the top of the casing.
(q) Public
				water supply wells shall be constructed in such a manner that any column/casing
				vents and blowoff valves are properly screened.