Ohio Administrative Code › Title 3745 - Ohio Environmental Protection Agency › Chapter 3745-9 - Water Well Standards › Section 3745-9-06 - Well construction, specific geologic conditions

Current
			 through all regulations passed and filed through July 1,
			 2024
(A) In addition to
			 the requirements of rule
			 3745-9-05 of
			 the Administrative Code, a well completed in specific geologic conditions shall
			 be constructed according to the following procedures:
(1) Where consolidated formations are
			 encountered within twenty-five feet of the ground surface, an oversized
			 borehole shall be drilled and the annular space shall be filled with grout by
			 pressure grouting.
(2) A well
			 completed where multiple aquifers are present shall have the casing extend
			 through aquifers that are not contributing to the water supply of the well. The
			 annular space contiguous to aquifers that are not contributing to the water
			 supply of the well shall be filled with grout by pressure grouting.
(3) A well completed in confined aquifers
			 shall have the casing extend through the confining layer to the top of the
			 aquifer. The annular space contiguous to the confining formation shall be
			 filled with grout by pressure grouting. Filter packs and formation stabilizers
			 shall not extend significantly into a confining formation or allow
			 interconnection of two separate aquifers along the annular space.
(4) A well completed in aquifers with
			 hydrostatic heads greater than the land surface elevation shall have casing and
			 grout installed to protect the aquifer, prevent erosion of the overlying
			 geologic materials and confine the flow to within the casing, and shall be
			 constructed according to the following procedures:
(a) If the anticipated flow at the ground
			 surface is not excessive, after the borehole is drilled, and the casing set,
			 the water in the casing may be pumped to lower the water level in the casing
			 and the annular space. The annular space shall then be filled with cement grout
			 by pressure grouting. The density of cement grout shall be sufficient to
			 control flow in the annular space, but no less than that required by rule
			 3745-9-07
			 of the Administrative Code.
(b) If
			 the water flow at the ground surface is anticipated to exceed five gallons per
			 minute, an upper enlarged borehole shall be drilled partially into the
			 confining formation. The upper enlarged borehole shall be at least four inches
			 in diameter larger than the nominal diameter of the outer well casing. The
			 annular space between the upper enlarged borehole and outer well casing shall
			 be filled with cement grout by pressure grouting. The outer casing may be left
			 as permanent casing once the well is completed, or it may be removed. Where
			 outer casing is not removed, the casing shall be withdrawn at least five feet
			 to ensure grout contact with the formation.
(i) If the confined aquifer is consolidated,
			 a smaller diameter borehole shall be drilled through the upper enlarged
			 borehole, the inner casing shall be firmly seated into the bedrock, and the
			 remaining annular space shall be filled with cement grout by pressure grouting.
			 The density of cement grout shall be sufficient to control flow in the annular
			 space, but no less than that required by rule
			 3745-9-07
			 of the Administrative Code.
(ii) If
			 the confined aquifer is unconsolidated, a smaller diameter borehole shall be
			 drilled through the upper enlarged borehole, with casing and a screen installed
			 into the confined aquifer. The well shall be double-cased, and the remaining
			 annular space filled with cement grout by pressure grouting. The density of
			 cement grout shall be sufficient to control flow in the annular space, but no
			 less than that required by rule
			 3745-9-07
			 of the Administrative Code.
(c)
										Flowing wells
			 shall be completed at the surface to ensure water does not flow from under the
			 well cap.
(d)
										Flowing well discharge control shall be provided to
			 conserve ground water and to prevent the loss of artesian head by preventing or
			 reducing continuous discharges. Flow control shall consist of one of the
			 following methods:
(i)
											The extension of the well casing to an altitude
			 corresponding to that of the artesian head.
(ii)
											Installation of
			 a vermin proof cap, well pitless adapter or wire spud, or a point of discharge
			 that complies with paragraph (A)(4)(e) of this rule.
(iii)
											Installation of
			 flowing well or spool type pitless unit, when installed within the
			 manufacturer's specification for rated pressure.
(iv)
											Other methods
			 approved by the Ohio EPA.
(e)
										After all uses
			 for the public water system are met, flowing wells may discharge up to ten
			 gallons per minute when the public water system's owner demonstrates that a
			 suitable discharge point exists on the owner's property, that the flow control
			 discharge line can be adequately protected from any possible cross connection,
			 and when one of the following conditions exist:
(i)
											Control of the
			 flow is not practical due to excessive hydrostatic pressure.
(ii)
											Control of the
			 flow will likely result in the production of sand or turbidity in the
			 water.
(iii)
											The discharge will not adversely affect surrounding
			 users of ground water or impact surface water drainage.
(iv)
											The discharge
			 line from the well shall either be protected by an air gap with an animal guard
			 or a backflow prevention device.
(5) A well completed in a cavernous formation
			 or mine shall be constructed according to the following:
(a) A cavernous formation or mine that is not
			 being used as a source of water shall have casing installed through the
			 formation or mine, as follows:
(i) If a
			 cavernous formation or mine is greater than twenty-five feet below ground
			 surface, then the formation or mine shall be filled with cuttings, clean gravel
			 or grout. Packers or shale traps shall be installed at the top and bottom of
			 the formation or mine. The annular space shall then be filled with grout by
			 pressure grouting.
(ii) If a
			 cavernous formation or mine is less than twenty-five feet below ground surface,
			 casing shall be installed in an enlarged borehole and the annular space shall
			 be filled with a cement grout containing additives that promote bridging of the
			 cavernous formation or mine by pressure grouting to a depth of at least five
			 feet beyond the formation or mine.
(b) If a cavernous formation or mine will be
			 the source of water supply, then a packer or shale trap shall be installed at
			 the top of the formation or mine and the annular space shall be filled by
			 pressure grouting with grout.
(6) A well encountering brine producing
			 formations shall be constructed according to these procedures. Brine producing
			 formations that are encountered during drilling shall have casing installed
			 throughout the entire formation. The annular space contiguous to the brine
			 producing formation shall be filled with grout by pressure grouting, or the
			 well shall be sealed to an elevation higher than the top of the brine producing
			 formation. Grout that is not adversely affected by the brine water shall be
			 used for sealing the well or annular space.
(7) Except when a well is completed in the
			 upper-most weathered portion of a consolidated formation, a well completed in a
			 consolidated formation shall have the casing extend into the formation so that
			 the well casing will not settle or shift, and will have a proper annular
			 seal.