State Well Codes

Well construction prohibited along sections of Whitewood Creek and sections of Belle Fourche River -- Variance. Alternative well construction may be used to construct wells which are completed into the Dakota aquifer in the Kennedy Basin, Sioux Ridge, the Canadian Shield, and the eastern portion of the Williston Basin if the following requirements are met, see 74:02:04:35, and for alternative construction requirements for Inyan Kara wells see 74:02:04:36. No well may be constructed to allow production from more than one aquifer unless approved by the chief engineer or the water management board.

Hard rock wells are defined as wells that do not require casing throughout their entire depth. Hard rock is defined as Precambrian aged rock and igneous or metamorphic rock. The well casing of hard rock wells shall be pressure grouted with cement grout from the bottom of the casing to the ground surface or to the bottom of a pitless adapter or pitless unit, if used. The minimum allowable casing length is 20 feet. If a pitless adapter or pitless unit is used, at least 20 feet of casing must be installed below the pitless adapter or pitless unit.

Only wells with well reports that describe the original construction may be deepened without an approved special standard unless the well is recased and resealed to meet current minimum well construction standards. If deepening of an existing well results in access to a new aquifer then prior to completion of deepening work all previous aquifers, including aquifers that have gone dry or are low producing, shall be cased and sealed off using methods detailed in OAR 690-210.

"Certain conditions may require increased distances of certain wells from potential contamination sources or known contamination and the decision shall be made in consultation with the Department. These include but are not limited to:
a. Type I and IV wells with less than twenty feet of casing
b. Type I wells where fractured rock is at the surface
c. Type II or III wells with no confining layers between the screened zone(s) and the ground surface
d. Type IV wells where no confining layers overlie the open-hole limestone or the limestone is at shallow depth
e. Type V wells because they are under water-table conditions"

High solids sodium bentonite grout shall have a minimum of 20% solids and be mixed per manufacturer’s specifications with water and/or other required additives. When high solids sodium bentonite grouts are used, a vapor barrier at the land surface at least the width of the annular space made of suitable materials, as approved by the Department, such as native soils, gravel, sand, or thermoplastic material, is required for public safety and structural stability of the well.

Water used in the drilling process shall be obtained from a source that will not result in chemical or biological contamination of any aquifer. Water taken directly from ponds, lakes, streams or other surface water sources shall not be used.

Well to be sealed w/ watertight cap or seal when it is temporarily abandoned, any well removed from service for longer than 36 months shall be permanently abandoned. Any well that acts as a source of contamination shall be repaired or permanently abandoned immediately after receipt of notice. To be filled by forced injection of grout or pouring through tremie pipe from bottom to surface in one continuous operation, unless compacted clay is used. The bored well shall be abandoned immediately upon being permanently taken out of service.

To allow for grout, must have upper drill hole 4 inches greater diameter than nominal diameter of permanent casing. Watertight unperforated casing to extend and be sealed to at least 5 ft into confining formation immediately overlying the artesian water-bearing zone. Minimum 18 ft of casing and seal required in all cases. If flowing, shall be equipped w/watertight mechanical cap, threaded or welded, and control valve. All artesian wells to be tested for shut-in pressure (psi) and rate of flow (ft^3/sec) or gpm under free discharge conditions.

All water used in the construction, alteration, repair, hydrofracturing, surging or abandonment of a well shall be potable.

Fuel storage tanks should be located as far as possible from wells or animal waste storage facilities.

If water-bearing interval overlain by unconsolidated deposits with significant clay beds, to have watertight, unperforated casing to minimum of 5 ft into clay interval. Oversized drill hole to be 4 inches greater than nominal diameter of casing to be constructed to same depth, unless clay interval is less than 13 ft below land surface in which case oversized drill hole must be to depth of 18 ft below land surface. May extend casing deep if needed. Smaller diameter casing, liner, and well screen may be installed. Annular space to be completely grouted in accordance with OAR 690-210-0310 through 690-210-0360.

If penetrating artesian aquifer shall have upper oversized drill hole minimum ≥ 4 inches than nominal diameter of watertight, unperforated casing which shall extend ≥ 5 ft into confining interval immediately overlying artesian zone. In all cases, minimum of 18 ft casing and seal is required. If cement grout placed from bottom by approved method, diameter of upper oversized drill hole to be ≥2 inches nominal diameter of casing. If artesian pressures are encountered in the absence of a confining layer, casing and seal requirements to be determined by Director, or person constructing well may conform w/minimum standards for artesian wells w/confining interval. If flows at surface, to be equipped with control valve and watertight mechanical cap, threaded or welded. All flowing artesian wells to have pressure gauge on a dead-end line. Petcock valve to be placed between gauge and casing.

20 ft. recommended

5 ft, includes roof, eaves, and other additions to structure that hinders ability of drilling machine to get over well. Does not include pump houses or other easily removed outbuildings. Rain water gutter downspouts and drains are exempt.

A new water supply well may be constructed at the site of an abandoned septic tank or drain field one year after taken out of use, but must not be constructed through the abandoned septic tank or septic drain line.

With Surface Casing - watertight, welded, steel plate at least 3/16 inch in thickness to be installed between the inner production casing and the outer surface casing at the wellhead. A watertight fill port with threaded cap may be installed for the purpose of placing additional filter pack material in the well. W/O Surface Casing - if permanent casing not installed, filler tubes are to be used, oversize well bore having nominal diameter of ≥4 inches than nominal diameter of permanent casing. A suitable plug to be installed between filter pack and grout seal. Watertight fill pipe with threaded cap may be installed for purpose of placing add'l filter pack material. O.D. of fill pipe shall not exceed 1/2 thickness of grout seal surrounding permanent well casing and to be centered in annular space.

Shall nave nonperforated, watertight casing meeting min. specs in Table 210-1 to minimum of 18 ft below land surface. Drive casing > 3 1/2 in. shall comply w/min. specs OAR 690-210-0190. Upper drill hole ≥4 in nominal diameter of permanent casing shall extend > 18 ft below land surface. Annular space to be filled with grout. If temporary casing is used during construction, it must be removed during placement of the grout

All water used in the construction, alteration, repair or abandonment of water supply wells shall be potable.

To be sealed as required by OAR 690-210 and be at least 4 inches greater than nominal inside diameter of permanent casing.

Must be approved by Dept. before work begins.

There are no statewide construction for private water wells. Some municipalities, however, do have standards.

300 ft. from outside perimeter of existing or proposed waste lagoon for a feedlot or confined animal feeding operation

Joints to be threaded, welded, or glued. To be watertight & grouted from land surface to min depth of 10 ft. below surface and to further depth necessary to and seated into impervious stratum above source aquifer. Where impervious stratum does not occur, casing to be extended as far as practicable below water table, at least 10 ft below seasonal stage. Wells may not be completed in salt water zones.

To be filled with uncontaminated surface clay or grout to w/in 6 ft of land surface. Lining to be removed from top 5 ft and min. of 2 ft of cement grout to be installed. Top 4 ft shall be filled w/compacted uncontaminated native soil, unless otherwise directed by the Board.

To be filled with cement grout or cement/bentonite to minimum 10 ft depth, or further depths as needed to prevent pollution.

To be minimum 30 ft depth. Pilot hole must first be constructed, with cement installed to 3 ft depth around surface casing, then remaining bore hole can be installed, then production casing installed.

If used for the bentonite seal portion below the cement grout portion of the surface seal, the grout shall contain a minimum 20% solids by dry weight.

Other governmental agencies may require wells to be located at distances greater than the minimum distances set for in this rule. If not prohibited by well owner or governmental agency requirements, groundwater wells not used for drinking water may be located closer to possible pollution source than minimum distances if all following conditions are met: if pollution source is not a wastewater lagoon or subsurface septic tank, drilled has advised well owner prior to drilling that well is subject to contamination, proposed well owner notifies the Board that he authorizes location closer than minimum location standard, outside water-tight casing is properly cement grouted or completed with 10 ft bentonite in lower 1/2 portion and 10 ft cement grout in upper 1/2 portion at least 20 ft down from land surface or pitless adapter connection.

All pipe materials must conform to ASTM, CSA, and AWWA standards approved by the department, pipe fittings must also conform to NSF standard 61.

Couplings used to join well casings of dissimilar materials or sizes shall conform to following criteria: Have same or better strength and rigidity of well casing being joined together, be composed of cast steel unit joined by a minimum of 5 steel bolts spaced uniformly around circumference of coupling, use ramped compression gasket seal that fits between upper and lower portions of coupling, ensure a minimum of 3 inch length of the top and bottom casing end is contained within both top and bottom pieces of coupling.

Shall be a factory manufactured forged steel unit with a cutting edge.

Required for wells discharging to a non-pressurized reservoir tank. Shall be installed no greater than 20 ft from top of submersible pump.

All casing shall be watertight, ad extend above finished grade minimum of 12 inches. Top of casing cut to so well cap will sit flush for tight seal. Defective, visibly damaged, used or reject pipe shall not be used as casing or liner pipe. Pipe withdrawn from a well or test hole during initial construction may be used as casing or liner pipe for another well if pipe not impregnated with contaminant, meets applicable requirements of new pipe and has been visually inspected by registered contractor for pinholes, cracks or other damages. Nominal pipe size of permanent primary casing shall be min. 5 inches, sized to allow adequate water and allow for installation and maintenance of pump and well equip. Casing shall extend to top of aquifer, or top of non-water bearing formation immediately above aquifer, shall not extend <25 ft below ground surface except wells in unconsolidated and consolidated aquifers where conditions indicate potable water is not present at depths >25 ft. Casing shall extend at min 10 ft depth, no exceptions. See Location-General and Disinfection-General for wells w/casing between 15-25 ft total depth. If non-potable water encountered, casing shall extend to point necessary to prevent non-potable water from entering aquifer containing potable water, and below aquifer containing potable water, lower part of well to be filled w/cement or bentonite grout to prevent exchange of waters.

Annular space contiguous to confining layers, or non-potable aquifer to be filled w/cement or bentonite grouts by pressure grouting or dry pouring methods. Grout to be continuous along permanent casing, and grouted between permanent and temporary casing when removed. If oversized borehole, annular space to be minimum 1& 1/2 inch per side for wells < 14 inch diameter measured from outside of casing, or min. 1 inch per side if measured from outside of casing coupling, min. 2 inches per side for wells >14 inches diameter, min. 1 inch per side from outside diameter of secondary casing. Wells >20 inches diameter, annular space to be ≤6 inches per side (12 inches ttl) for wells ≤30 ft depth, and ≤ 4 inches per side (8 in ttl) for wells >30 ft depth. Except for dry driven grout method, total volume of sealing materials must not be <80% of volume of annular space. Grout not required along length of smaller diameter casing extensions for large diameter wells using fiberglass casing. Grout to be placed from 6 inches above to 6 inches below the joint between smaller and larger casing. Annular space adjacent to smaller diameter casing to be filled with clean clay. Where annular space in borehole is consistently dry, consider type of grout used. Pressure grouting w/bentonite or cement grout slurries to be placed in continuous operation w/materials of same density as grout placed in borehole. If tremie or conductor pipe used, may be left in place if well <100 ft depth if filled with grout. Flowing wells with grouting at >100 ft keep tremie pipe submerged min. 10 ft below grouting surface at all times. Acid soluble cellulose fiber additives may be added to the grout slurry.

Exceptions noted in Chapter 3701-28-02 of Administrative Code: Scope, responsibility for compliance, and applicability of rules. Shall not have any physical cross-connections to a public water system.

Sodium hypochlorite must be ≥ 5% strength and used before expiration date. Do not use products w/fragrance additives. Calcium hypochlorite products should not be used to disinfect wells completed in limestone aquifers, or where well water has high levels of dissolved calcium unless recommended by manufacturer or department. Distilled white vinegar approved. Except for sodium hypochlorite and vinegar, all other products must comply with Ansi/NSF 60 and be designed as well disinfectant and/or cleaning agent.

May only be used for sealing wells in accordance with the special conditions described in rule 3701-28-17 of the Administrative Code.

Med-Large 300 ft., small (#animals between medium &3% of a medium CAFF) 150 ft, small (3% rounded to lower end of medium CAFF and holding pens no grassed cover, stables manure piles, fabricated manure storage and water or treatment buildings) 50 ft.

100 ft.

New private water system on new building lot shall be w/in 2% from boundary of minimum isolation distance requirements for any on-site sewage treatment system and 10% for all other isolation distances required. Replacement system at existing building shall be w/in 10% of minimum required distance w/o requirement for variance when maximum practical isolation distance from all potential sources of contamination and structures is maintained. If isolation distances cannot be met, greatest practical distance shall be maintained from sewage systems, petroleum tanks, roads and right of ways, waste application staging areas and landfills, priority in this order. Well owner shall be responsible for maintaining isolation distances. If total casing length 15-25 ft, requires continuous disinfection in accordance w/rule 3701-28-15 of the Administrative Code or may be installed where the isolation distances are doubled, and testing can meet the bacterial standards in paragraph (J) of rule 3701-28-04 for two samples collected during opposite seasons within a one year period.

10 ft.

If well located within grassed pasture used by large animals, well shall be surrounded by a fence with all sides at least 5 feet from well.

Must allow access for maintenance, alteration, removal and repair or components. Must be constructed above ground, except if room is in basement, basement offset, crawl space or buried vault that does not accumulate water.

Water storage tanks and reservoirs shall meet the criteria of paragraphs (A) and (B) of rule 3701-28-12 of the Administrative Code and also comply with all other applicable provisions of rule 3701-28-12 of the Administrative Code. For the purpose of this rule a storage tank does not include a pressure tank.

The top of the completed well casing shall extend a minimum of 18 inches above the ground and appropriate steps shall be taken to prevent damage to well casings.

All wells shall be constructed to prevent contaminants from entering the borehole from the ground surface by sealing the annular space around the outermost casing. If surface casing (outer casing) is used then there must be a seal between the surface casing and the production casing at the ground surface. When necessary, annular seals will be required to prevent inter-aquifer exchange of water, to prevent the loss of hydraulic head between hydrogeologic zones, and to prevent the flow of contaminated or low quality water. Sealing operations shall be made with an office of the state engineer approved sealant. Casings shall be centralized within the interval to be sealed so grout or sealing materials may be placed evenly around the casing. If a well is completed less than 20 feet below ground surface, the seal shall be placed from ground surface to the bottom of the blank casing used. However, if a monitoring well is completed less than 20 feet below ground surface, the seal shall be placed for the maximum length practical in order that the well is constructed to prevent contamination, to prevent inter-aquifer exchange of water, to prevent flood waters from contaminating the aquifer, and to prevent infiltration of surface water. The annular seal shall extend to ground surface unless a pitless adapter is installed. For wells completed with a pitless adapter, the top of the seal shall extend to one foot below the pitless adapter connection. ADDITIONAL REGULATIONS FOR ARTESIAN SEALS.

Required before drilling, construction, repair or deepen, replacement, or supplement a well.

1) The state engineer shall require a meter on each new 72-12-1.1 domestic well permitted:
(a) within a domestic well management area;
(b) when a metering requirement is imposed by the courts;
(c) for drinking and sanitary domestic use that is incidental to the operations of a governmental, commercial, or non-profit facility;
(d) for multiple households domestic use;
(e) as a supplemental 72-12-1.1 well; the 72-12-1.1 domestic well being supplemented shall also require a meter; and
(f) as a multiple use well such that the diversion of water for domestic use is separately metered.
(2) The state engineer may require a meter on a new 72-12-1.1 domestic well:
(a) permitted for single household domestic use;
(b) permitted to accompany a residence or other dwelling constructed for sale;
(c) as a condition of a permit to repair or deepen a 72-12-1.1 domestic well;
(d) as a condition of a permit to amend the type of domestic use of a 72-12-1.1 domestic well permit; or
(e) as a condition of a permit to transfer a valid, existing water right to a 72-12-1.1 domestic well permit in accordance with subsection E of 19.27.5.14 NMAC.

50 ft.

All wells shall be set back from potential sources of contamination such as, but not limited to, septic tanks and sewage leach fields, cemeteries, livestock lagoons and sewage lines, in accordance with applicable federal, state, or local requirements.