SECTION 252:626-7-4. Ground water

(a)   A ground water source includes all water obtained from drilled, bored or driven wells. A test well is required where sufficient information is not available to assure adequate quality and quantity of water.

(1)   Quantity.

(A)   Provide a minimum of 2 wells for community water systems unless a standby source with adequate capacity is available.

(B)   Where ground water is the sole supply source for a community water system, the total developed ground water capacity must equal or exceed:

(i)   the design maximum day demand, and

(ii)   the design average day demand, with the largest producing well out of service.

(2)   Quality.

(A)   Bacteriological quality.

(i)   Underground waters subject to a low degree of contamination shall require chlorination if:

(I)   the coliform count averages not more than 50 per 100 ml in any 1 month, and

(II)   the turbidity does not exceed 5 NTU.

(ii)   Disinfect every new, modified or reconditioned ground water source according to AWWA standard specifications after the completion of work and placement of permanent pumping equipment.

(iii)   Upon completion of the well, collect at least 2 bacteriologically safe samples on consecutive days. Collect samples after chlorine used in disinfecting the well has been completely dissipated. Submit the records to the DEQ.

(iv)   If any samples show the presence of coliform bacteria, take additional samples to determine the degree of contamination and treatment required.

(B)   Physical, chemical, and radiological quality.

(i)   Test every new, modified, or reconditioned ground water source for applicable physical, chemical, and radiological characteristics contained at OAC 252:631-3-1 by submitting a representative sample to a certified laboratory or the State Environmental Laboratory and report results to the DEQ.

(ii)   Collect samples at the conclusion of test pumping.

(iii)   Additional field determinations or special sampling procedures may be required by the DEQ.

(C)   Test results. The results of the required testing shall be used to determine the extent of water treatment required. If all parameters are in compliance with the standards set forth in the Safe Drinking Water Act and OAC 252:631, no treatment will be required.

(3)   Location. In the selection of a site:

(A)   evaluate the following:

(i)   type of well construction to be utilized,

(ii)   depth to water bearing zones,

(iii)   type of formations to be penetrated, and

(iv)   proximity of existing or possible future sources of pollution such as sewers, seepage pits, soil absorption fields, privies, sink holes, dumping areas, caves, test holes, abandoned wells, borings, industrial lagoons, private water supply developments, fuel storage tanks, and other underground construction,

(B)   locate wells at the highest point of the premises consistent with other facilities and surroundings but always protected against surface drainage,

(C)   do not locate wells:

(i)   in a ravine where the well site may be flooded or within 300 feet horizontally from any existing or potential source of pollution including water bodies. If a wellhead delineation model has been performed for the site, the separation distance must conform to the model prediction for potential contamination,

(ii)   within three hundred feet (300') of a proposed or existing sewer line,

(iii)   within one hundred feet (100') of a private property line, or

(iv)   within fifty feet of a publicly owned property line, and

(D)   locate pump room floor at least 2 feet above the 100-year flood plain

(b)   Testing and records. The permittee shall:

(1)   provide yield and drawdown testing procedures for the well(s) in the plans and specifications, approved by the DEQ, and make the results for completed wells available for final inspection. Yield and drawdown tests must:

(A)   be performed on every production well after construction or improvements, which affect the well capacity, and prior to placement of the permanent pump,

(B)   have test methods clearly indicated in specifications,

(C)   determine well capacity with the pumping rate at maximum anticipated drawdown, pumping rate must be at least 1.5 times the quantity anticipated,

(D)   test pump the well at 1.5 times the design pumping rate for at least 24 hours or until the drawdown has stabilized for a minimum of 6 hours, and

(E)   provide the following test data to the DEQ prior to completion of the well:

(i)   test pump capacity-head characteristics, and overall efficiency,

(ii)   static water level and water level at design pumping rate,

(iii)   depth of test pump setting,

(iv)   time of starting and ending each test cycle, and

(v)   zone of influence for the well(s).

(2)   test the well for plumb and alignment in accordance with AWWA standard specifications. The specifications must cite the AWWA standard and describe the method to be used.

(3)   submit well logs that shall contain:

(A)   samples collected at maximum 20-foot intervals and at each pronounced change in formation,

(B)   a record of drill hole diameters and depths, assembled order of size and length of casings and liners, length of the perforated section and type of perforations, or type and length of screen used, grouting depths, formations penetrated, water levels, and location of any blast charges. Where multiple water bearing formations are developed, give the elevation and length of each perforated or screened section.

(c)   General well construction.

(1)   Minimum depths of wells. Construct wells to a depth sufficient to ensure that safe water can be obtained. Water taken from depths of 20 feet or less shall require additional testing to determine the necessary level of treatment.

(2)   Minimum protected depths. Protect wells by watertight construction to a depth necessary to:

(A)   exclude surface contamination, and

(B)   seal off formations that are contaminated or yield undesirable water.

(3)   Well surface casing. Every well shall have a watertight surface casing extending at least 20 feet below the surface. A greater depth will be required in unconsolidated soils, karst formations or when necessary to eliminate contamination from the surface or upper formations.

(A)   Surface casing material. Surface casing shall only be made from ferrous material and must:

(i)   be new pipe meeting ASTM, AWWA, NSF or API specifications for water well construction,

(ii)   have minimum weights and thickness indicated in Appendix C,

(iii)   be capable of withstanding forces to which it is subjected,

(iv)   be equipped with a drive shoe when driven, and

(v)   have full circumferential welds or threaded coupling joints.

(B)   Internal casing materials. Internal casing material shall:

(i)   meet AWWA standards,

(ii)   meet NSF standards for contact with potable water,

(iii)   be resistant to the corrosiveness of the water,

(iv)   be able to withstand the stresses to which the well will be subjected during installation, grouting and operation, and

(v)   be equipped with a drive shoe when driven.

(4)   Packers. Packers must be made from an NSF approved material

(5)   Screens. Screens must:

(A)   be constructed of materials resistant to damage by chemical action of ground water or cleaning operations,

(B)   have sizes of openings based on sieve analysis of formation and gravel pack materials to permit maximum transmitting ability without clogging or jamming,

(C)   have sufficient diameter to provide adequate specific capacity and low aperture entrance velocity. The entrance velocity must not exceed 0.1 ft/s,

(D)   be installed so that the pumping water level remains above the screen under all operating conditions, unless measures are provided to protect the screen from being corroded, and

(E)   be provided with a bottom plate or washdown bottom fitting of the same material as the screen, where applicable.

(6)   Grouting requirements. Surround surface casing with a minimum of 1-½ inches of grout to the depth of the surface casing.

(A)   Cement grout.

(i)   Cement conforming to ASTM Standard C150, with not more than 6 gallons of water per 94 pound sack of cement, must be used for 1-½ inch annular openings.

(ii)   Additives used to increase fluidity are subject to approval by the DEQ.

(B)   Concrete grout.

(i)   Equal parts of cement conforming to ASTM Standard C150, and sand, with not more than 6 gallons of water per 90-lb. sack of cement may be used for annular openings larger than 1-½ inches.

(ii)   Where an annular opening larger than 4 inches is available, gravel not larger than ½ inch in size may be added.

(C)   Application.

(i)   Provide sufficient annular opening to permit a minimum of 1-½ inches of grout around permanent casings, including couplings.

(ii)   When completing a gun perforated well with an annular opening less than 4 inches, install grout under pressure by means of a grout pump from the bottom of the annular opening upward in one continuous operation until the annular opening is filled.

(iii)   Concrete grout used in an annular opening of 4 or more inches and less than 100 feet in depth, may be placed by gravity through a pipe installed to the bottom of the opening in one continuous operation until filled.

(iv)   Clay seals with at least ten percent (10%) swelling bentonite may be placed by gravity when the annular opening exceeds 6 inches and the depth is less than 100 feet.

(v)   Provide the casing with sufficient guides welded to the casing to permit unobstructed flow and uniform thickness of grout.

(7)   Well floor.

(A)   Construct the well floor with reinforced, watertight concrete not less than 6 inches thick with a footing of at least 12 inches.

(B)   Provide a watertight joint between the concrete motor base and floor.

(C)   Extend the floor or concrete apron at least 2 feet from the well excavation line in all directions. Where necessary, extend it an additional distance to support the pump or casing.

(D)   Construct the top of the floor slab or apron at least 6 inches above the surrounding ground.

(E)   Thoroughly compact the area below the floor or apron prior to pouring the concrete.

(F)   Slope the floor or apron at least 1/8 inch per foot away from the well casing and allow for drainage.

(8)   Upper terminal well construction.

(A)   Extend the casing at least 12 inches above a well house floor or concrete apron.

(B)   Terminate the top of the well casing at least 5 feet above the 100-year flood plain, or the highest known flood elevation, whichever is greater.

(C)   Seal the top of the casings with a sanitary well seal to properly protect against entrance of contamination into the well.

(D)   The discharge piping must:

(i)   have control valves and appurtenances located above the well floor,

(ii)   be equipped with a check valve, a shutoff valve, a pressure gauge, a flow meter, and a smooth nosed sampling tap located upstream of the shutoff valve and at a point where positive pressure is maintained,

(iii)   be equipped with an air relief valve located upstream from the check valve. The exhaust/relief piping must terminate in a down-turned position at least 18 inches above the floor and covered with a 24 mesh corrosion resistant screen,

(iv)   be valved to permit test pumping, pumping to waste and control of each well,

(v)   enclose all exposed piping, valves and appurtenances in the well house to protect against physical damage, tampering and freezing. The well house design shall be sufficient to accommodate the disinfection equipment,

(vi)   be properly anchored to prevent movement,

(vii)   be protected against surge or water hammer,

(viii)   must not be directly connected to a sewer, and

(ix)   provide a concrete splash pad outside the wellhouse where the blow-off valve discharges to protect the well house foundation from erosion.

(E)   Access to disinfect the well is required.

(F)   Design the well vent to:

(i)   vent the casing to atmosphere, unless the design is for vacuum operation,

(ii)   construct the vent of 1 ½ inch minimum diameter metal pipe and be fitted into the well cap or pump base so as to form a water-tight connection,

(iii)   terminate the vent in a full 180-degree bend not less than 24 inches above the well floor slab or apron, and

(iv)   screen the opening in the vent with a corrosion resistant screen. The openings in the screen must not be larger than 24-mesh.

(G)   Provisions for measurement of water levels in the completed well are required to:

(i)   Provide an accurate draw-down gauge, air pipe, direct measurement tube, or other access for measuring the water level in the well.

(ii)   Make the connection between the air tube and the pump base watertight when an air pipe passes through the pump base.

(iii)   Extend tubes for direct measurement of water levels 24 inches above the well floor slab, and tightly cap with a bolted flange or a screwed cap.

(iv)   Provide corrosion resistant water level measurement equipment.

(9)   Pumps.

(A)   Line shaft pumps. Wells equipped with line shaft pumps must:

(i)   have the casing firmly connected to the pump structure or have the casing inserted into a recess extending at least 1 inch into the pump base,

(ii)   have the pump foundation and base designed to prevent water from coming into contact with the joint, and

(iii)   have a heavy gasket installed between the pump base and the pump pedestal.

(B)   Submersible pumps. Where a submersible pump is used:

(i)   effectively seal the top of the casing against the entrance of water under all conditions of vibration or movement of conductors or cables,

(ii)   firmly attach the electrical cable to the riser pipe at 20 foot intervals or less, and

(iii)   pumps with mercury seal are not permitted.

(10)   Aquifer types and construction methods - special conditions.

(A)   Gravel pack wells.

(i)   Use gravel pack that is well rounded, 95% siliceous material, smooth and uniform, free of foreign material, properly sized, washed and disinfected immediately prior to or during placement.

(ii)   Install gravel pack in one uniform continuous operation throughout each screened interval.

(iii)   Use Schedule 40 pipe, steel pipe or equivalent incorporated within the pump foundation and terminated with screwed caps at least 12 inches above the pump house floor or concrete apron when using gravel refill pipes.

(iv)   Surround gravel refill pipes located in the grouted annular opening by a minimum of 1-½ inches of grout.

(v)   Provide protection from leakage of grout into the gravel pack or screen.

(B)   Radial water collector as a raw water source.

(i)   Indicate the locations of all caisson construction joints and porthole assemblies,

(ii)   Reinforced the caisson wall to withstand the forces to which it will be subjected,

(iii)   Locate radial collectors in areas and at depths approved by the DEQ,

(iv)   Assure that radial collectors are essentially horizontal,

(v)   Cover the top of the caisson with a watertight floor,

(vi)   Protect all openings in the floor from the entrance of foreign material, and

(vii)   Do not place the pump discharge piping through the caisson walls.

(C)   Limestone wells. Where wells are in limestone areas, the DEQ will determine surface casing and grouting requirements. The surface casing must extend at least 20 feet into the formation.

(D)   Naturally flowing wells.

(i)   Provide provisions to control flow.

(ii)   DEQ may require special protective construction, if erosion of the confining bed appears likely.

(11)   Pitless well units.

(A)   Pitless well adapters are not allowed.

(B)   Pitless units shall meet the standards of PAS-97-CC (04) as developed by the Water Systems Council, as listed in the PAS-97, Appendix C, and shall:

(i)   be shop-fabricated from the point of connection with the well casing to the unit cap or cover,

(ii)   be threaded or welded to the well casing,

(iii)   be of watertight construction throughout,

(iv)   be of materials and weight equivalent and compatible to the casing,

(v)   have field connection to the lateral discharge from the pitless unit of threaded, flanged or mechanical joint connection,

(vi)   terminate at least 12 inches (30 centimeters) above the well slab, and

(vii)   terminate 5 feet (1.5 meters) above the 100-year flood plain or the highest known flood elevation whichever is higher.

(C)   Design the pitless unit to provide:

(i)   access to disinfect the well,

(ii)   a properly constructed casing vent meeting the requirements of OAC 252:626-7-4(c)(8)(F),

(iii)   a cover at the upper terminal of the well that will prevent the entrance of contamination,

(iv)   a contamination-proof entrance connection for electrical cable,

(v)   an inside diameter as great as that of the well casing, up to and including casing diameters of 12 inches, to facilitate work and repair on the well, pump, or well screen, and

(vi)   a well floor constructed in accordance with OAC 252:626-7-4(c)(7).

(D)   If the connection to the casing is by field weld, the shop-assembled unit must be designed specifically for field welding to the casing. The only field welding permitted will be to connect a pitless unit to the casing.

(d)   Disinfection of wells. Disinfect all wells and gravel for gravel-pack wells according to current AWWA standard specifications.

(e)   Disinfection of ground water. Provide chlorination facilities for all ground water systems. If bacteriological tests indicate the water is safe, the facilities may be maintained as standby; otherwise, full time chlorination will be required.

(1)   Provide a welded metal plate or a threaded cap for capping a well.

(2)   The contractor must provide protection to prevent tampering with the well or entrance of foreign materials while work is in progress.

(f)   Well abandonment. Seal test wells, abandoned wells and other existing wells not protected and maintained for future use, by methods necessary to restore the controlling geological conditions which existed prior to construction as directed by the OWRB.

(g)   Test and observation wells.

(1)   Test and observation wells must be:

(A)   constructed in accordance with the requirements for permanent wells, including surface casing, if they are to remain in service after completion as a water supply well, and

(B)   sealed, if not in use, according to OAC 252:626-7-4(f).

(2)   A construction permit is required before a test or observation well is converted into a permanent well.

(h)   Capping requirements.

(1)   Provide a welded metal plate or a threaded cap for the capping of a well.

(2)   The contractor shall provide protection to prevent the tampering with the well or entrance of foreign materials while work is in progress.

[Source: Added at 18 Ok Reg 1612, eff 6-1-01; Amended at 25 Ok Reg 2304, eff 7-11-08; Amended at 33 Ok Reg 1472, eff 9-15-16]