Section We 602.22 - Wells Drilled in Bedrock: Installation and Placement of Casing(a) A bedrock well shall have no less than 20 feet of casing.(b) A well casing for a bedrock well shall: (1) Extend above the ground surface: a. A minimum of 8 inches or, in areas prone to flooding, to a greater height sufficient to prevent entrance of surface water into the well; orb. For a well that is part of a public water system as defined in RSA 485:1-a, XV, a minimum of 18 inches.(2) Have a secure cover with an o-ring, gasket, or other seal to prevent the entrance of insects or other foreign matter into the well; and(3) Be placed to create a seal which prevents ground water or contaminants from entering the well at the bottom or anywhere along the length of the casing.(c) The following techniques shall apply to well casing placement:(1) A hole shall be drilled into the bedrock to a depth sufficient to allow the casing to be installed to a minimum depth of 10 feet into competent bedrock or to a greater depth, if necessary to accept the casing and provide a seat for the drive shoe on the end of the casing;(2) A well casing shall be installed to a minimum depth of 10 feet into competent bedrock;(3) A drive shoe shall be used to assist in sealing the casing into the bedrock when steel casing is used;(4) When plastic casing is used the seal shall be created by using a "Jaswell" type seal tip, shale packer or equal;(5) A "Jaswell" type seal tip, shale packer or functionally equivalent equipment may be used on steel casing if the casing is placed in an open hole cased with a larger diameter temporary casing to bedrock;(6) For a well that requires additional casing, as specified in We 602.14 and We 602.16, a water well contractor using cable tool drilling methods may use a "Jaswell" type seal tip, shale packer, or functionally equivalent equipment;(7) When cable tool drilling methods are used, a drive shoe shall not be required if a tapered hole with ledge drillings is used or the casing is grouted as specified in We 602.05;(8) The void area outside the casing shall be filled with cement grout, bentonite or ledge drillings or cuttings; and(9) For a well constructed on a known active hazardous waste remediation site, petroleum spill remediation site, or a site with unlined solid waste landfill, as identified in the department's remediation and initial response spill sites database, the void area outside the casing shall be filled with cement grout, bentonite grout, or a cement-bentonite grout mixture to prevent surface water from migrating along the well casing.(d) The above requirements shall not preclude the use of additional protective measures.(e) A "Jaswell" type seal tip, shale packer or functionally equivalent equipment shall not be used to remedy a failed drive shoe seal, or to remedy an inadequately cased well, in new well construction.(f) When drilling water wells in bedrock using air rotary drilling methods, water shall be injected into the well on a continuous basis at a rate sufficient to clean the well and prevent dust production during the drilling process.(g) Overflow discharge water lines installed to vent flowing artesian wells shall meet the following standards: (1) Overflow discharge water lines shall be equipped with a swing type check valve;(2) The end of the water line shall be equipped with a 1/4 inch mesh screen, or woven hardware cloth;(3) The end of the water line shall be terminated with an air gap, if practicable. If termination with an air gap is not practicable, the water line may be terminated in a bed of 3/4 inch or 1 1/2 inch crushed stone; and(4) Overflow discharge water lines shall not terminate directly into any surface water of the state.(h) For wells constructed as part of a public water system as defined by RSA 485:1-a, XV, the void area outside the casing shall grouted in accordance with We 602.05 to prevent surface water from channeling along the well casing.N.H. Admin. Code § We 602.22
Derived From Volume XXXVII Number 2, Filed January 12, 2017, Proposed by #12083, Effective 3/1/2017, Expires 3/1/2027.