State Well Codes

Must be approved for potable use. Pressurized tanks must be equipped with identification including size, max working pressure, and name of manuf. Non-pressurized (cisterns) must be constructed of material with structure to adequately withstand burial.

Not more than six gallons of clear water per 94-pound bag of Portland cement. Up to five percent, by weight, of bentonite clay may be used to improve flow and reduce shrinkage. No sand or gravel is to be used in cement grout.

Consisting of not less than one-half pound of commercial bentonite clay to one gallon of clear water.

Shall be watertight. Either "bell" type or coupling hubs or threaded couplings are approved. Hub couplings shall be of material meeting the specifications for plastic casings as stipulated in ARM 36.21.645. Solvent cemented joints shall be made in accordance with manufacturer's directions.

Annular space to this depth to be filled w/ grout. If formation of low permeability is not encountered, upper drill hole & unperforated casing to extend min of 18 ft. If temporary casing is to maintain drill hole, annular space to be kept full w/ cement grout or bentonite clay. Injection pipe to be capped w/ watertight seal or plug. May extend into other formation of lower permeability overlying the water-bearing zone. Suitable bridge to be installed in annular space between gravel pack & sealing material. Upper diameter of drill hole at least 3 in. > O.D. of production casing to extend from surface into clay. Upper drill hole & unperforated production casing to extend to min depth of 18 ft. below land surface. Watertight seal to be installed at top of gravel pack between permanent surface & production casing. When casing is installed, well bore to have diameter of at least 3 in. > surface casing.

Unperforated well casing shall extend into the confining stratum overlying the artesian zone. The casing shall be adequately sealed into the confining stratum so as to prevent surface and subsurface leakage from the artesian zone. If the well flows at land surface, it shall be equipped with a control valve so that the flow can be completely stopped. The well shall be completed with packers or appropriate sealing material that will eliminate leakage around the well casing.

An unperforated well casing shall extend to at least one foot below the known seasonal low water table. An upper drill hole having a diameter at least three inches greater than the nominal size of the permanent casing shall extend to at least 25 feet below land surface.

Required.

50 ft.

All water wells shall be constructed by a licensed water well contractor unless specifically exempted by statute.

Under reamed and sized according to sand and screen. Shall be disinfected with chlorine residual of 50 ppm unless is clean, pre-packaged gravel.

All wells shall have a check valve installed in the discharge line. All new unmetered wells larger than 6 inches in diameter shall have a minimum of 4 ft of straight pipe installed between the casing head and the check valve, and all other equipment connected on the discharge side of the check valve.

If SDR 17, depth to be 500 ft. If SDR 21, depth to be 250 ft. If SDR 26, depth to be 125 ft. May be allowed if justification for its use outweighs its risk of failure. AWWA Standards.

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.

AWWA Specs. Ground surface around casing shall slope to drain away from the casing.

Apply to wells that penetrate water bearing strata or are greater than 25 ft in depth. Licensed well contractor to decommission well. If less than 25 ft depth can be plugged by other than licensed contractor. Department of Environmental Quality requirement: Pressure grout from bottom to top. See Decommissioning Procedures approved by DEQ.

100 ft.

10 CSR 23-3.090 sets specific additional standards for certain regions in Missouri, including Area 1) limestone or dolomite area, Area 2) Central Western Missouri, Area 3) NW Missouri, Area 4) NE Missouri, Area 5) Missouri Bootheel and all major stream alluvial areas, Area 6) St. Francois Mtn area. 10 CSR 23-3.100 sets specific additional standards for Sensitive Areas designated either naturally occurring problems or fragile groundwater environment outlined in maps in Code of State Regulations (7/31/07).

Top 20 ft and bottom 30 ft of annulus must be grouted.

50 ft.

50 ft.

Stainless steel casing is not allowed for potable wells but only monitoring wells and environmental boreholes.

A drive shoe is required whenever driving casing. Must be A) made of steel or iron with hardened, beveled cutting edge B) have a wall thickness equal to or larger than the casing thickness and C) be threaded or welded to the bottom of the casing.

Must not be completed in limestone or dolomite bedrock unless overlain by at least 50 ft of unconsolidated material, sandstone or shale extending in all directions for minimum radius of 1 mile. If completed in limestone or dolomite and static water level is more than 10 ft above limestone/dolomite, steel casing must be installed into limestone/dolomite by driving casing with drive shoe through unconsolidated materials or sandstone not more than 10 ft into limestone/dolomite. If static water level is less than 10 ft above limestone/dolomite bore hole must be drilled a minimum of 3.0 inches larger, or 3.5 inches larger for casings deeper than 100 ft and larger than 12 inches inside diameter, than the outside diameter of the casing or couplings, whichever is larger. The bore hole must extend a minimum of 20 feet below the static water level. Steel casing must be installed to bottom of borehole.

If borehole extends more than 10 ft below bottom of screen, must be filled with grout from bottom of bore hole to within 10 ft or less of screen. Flowing well must be constructed with flow control and have outlet screened with noncorrosive mesh with openings of 1/16 inch or less. A casing that extends more than ten feet into limestone or dolomite bedrock must be installed in a bore hole a minimum of 3.0 inches larger, or 3.5 inches larger for casings deeper than 100 feet and larger than 12 inches inside diameter, than the outer diameter of the casing or couplings, whichever is larger. Must be constructed to prevent entry of flood water. Materials used in construction of a potable water-supply well that contact water must not exceed 8% lead except that solders and flux must not contain more than 0.2 % lead.

Additives must meet ANSI/NSF 60-2003e. Bentonite drilling fluids used to construct or repair a water-supply well must have a measurable chlorine residual at all times during drilling or repair, except for a remedial well where chlorine will interfere with water quality analysis or remediation.

The annular space between an inner casing and an outer casing must be grouted for its entire length by pumping neat-cement grout or cement-sand grout through a tremie pipe or through the casing as specified in part 4725.3050.

Must not be used for disposal or injection of surface water, groundwater or any other liquid, gas, or chemical. May be used for injection of water to conduct slug test if injected water was originally taken from that well or is potable.

20 ft.

50 ft.

100 ft from tanks, vessels, or components of a wastewater treatment unit. 50 ft from sand filter, peat filter, or constructed wetland. 50 ft for water treatment backwash holding basin, reclaim basin, or surge tank with direct sewer connection. 20 ft from water treatment backwash holding basin, reclaim basin, or surge tank, and associated piping, with a backflow protected sewer connection.

Shall be grouted to protect the artesian aquifer, prevent erosion of overlying geologic materials, and confine the flow to within the casing. Flowing well discharge control shall be provided.

If bedrock within 25 ft of surface, oversized boreholes drilled and grouted with neat cement to minimum depth of 25 ft. If area only where well developed in fractured, jointed or cavernous bedrock, casing may termination in formation only if there is not less than 25 ft of soil above bedrock, if no record of contamination and no connections to surface water.

An annular space between a permanent casing and temporary casing shall be grouted during temporary casing removal by pumping neat cement or bentonite grout, or by pouring bentonite chips, bentonite pellets, or granular bentonite, into the annular space. Granular bentonite shall not be poured into an annular space that contains drilling fluid or water.

10 ft.

A driven well point shall not be used as a water supply well without the written approval of the health officer. Drilling fluids or additives that contain guar gum or other biodegradable organic materials shall not be used during the drilling of a well.

Not allowed.

Bentonite with minimum solids content of 20% may be used to fill annular space when mixed as a slurry at 2 lbs bentonite per 1 gal. water, or in chip or pellet form and if hydrated per specifications when annular space is less than 20 ft depth. May not be used in contact with groundwater with pH below 4.0 or TDS greater than 1,000 mg/L. Sand-bentonite ratio may not be greater than 250 lbs sand per 50 lbs bentonite. Sand shall be "000" well gravel that meets the following: must be 95% silica sand, have uniformity coefficient not greater than 1.7, and have particle size range of 0.60 to 0.15 mm. Inside casing may be grouted with bentonite chips or pellets if drilling fluid, if present, is thinned to viscosity of less than 30 seconds and weight is less than 9 lbs/gal.

Specific regs, hydrofracturing. Shall not be conducted without approval from the Approving Authority.

All wells shall be extended at least 8 inches above final grade, 24 inches above finished grade in areas likely to flood.

For well screened in unconfined aquifer in Hydro Area 1 & 2, annular space shall be grouted to depth of at least 20 ft.

Wells in Hydro Area 2, depth of grouting may not be less than 30 ft. The annular space above the screen and below the grout shall be completely filled with clay, drill cuttings, or sand before grouting operations begin. For wells intended to have a yield of less than 5,000 gpd, the grout shall extend from a minimum of 5 ft into the first confining bed, which is at least 5 ft thick, to the land surface.

Use water from best possible source; public water supply, potable water supply, nonpotable or temporary well constructed for purposes of construction but must not have turbidity of more than 25 standards units, except when turbidity is due to oxidation of dissolved iron or manganese. Must have a color of not more than 25 standard units, and contain no objectionable odor. Chlorine compound added to water from public supply shall produce a free chlorine residual of at least 1.0 mg/L, potable supply shall have chlorine residual of at least 3.0 mg/L, and nonpotable supply shall be dosed with chlorine to produce minimum free chlorine residual of 50 mg/L. Driven wells may not be used for a potable water supply.

Wall thickness of precast concrete pipe should be minimum 3 inches thick and poured-in-place concrete at least 6 inches thick. Casing should be watertight to depth of production aquifer or depth of 20 ft. below preexisting ground surface, whichever is greater. Upper terminus of casing should extend 12 inches above pre-existing ground surface or 2 ft. above highest recorded flood, whichever is greater. With precast concrete pipe, annular space should be at least 4 inches larger than O.D. casing and should e sealed with neat cement grout or sand cement ground to depth below frost line. Intake should be perforated casing or loosely laid wall of stone, concrete block, or brick. Must be of strength to withstand pressures and seated to prevent settling.

Should have cover of reinforced concrete at least 4 inches thick, should rest on and overlap outer edge of well casing by 2 inches and should be constructed without joints. Pump sleeve sized to accommodate pump type and pump piping should be cast in place when cover fabricated. Top of cover should be sloped to drain away from sleeve. If manhole installed, should have curb extending at least 2 inches above top of cover and cast in place with cover fabrication. Manhole should have overlapping cover with sides extending downward around curb at least 1 &1/2 inches. Joint between curbing and cover should be watertight with plastic sealing compound and manhole cover locked or bolted in place.

Pipe-thread compound must be NSF approved for water wells and couplings with recessed ends and tapered threads, either connect well point to 5 ft. length of casing or to a string of well casing, or connect well point to a coupling and place well point into 5 ft. length of oversized casing, attaching additional lengths of casing if desired.

Mixture of 1 94-lb bag of Portland cement (ASTM Standard C150, Type I or API Standard 10, Class A) and not more than 6 gallons of clean water. Bentonite (API Standard 13A) up to 2% by weight of cement shall be added to reduce shrinkage Other additives may be used described in ASTM Standard C494 to increase fluidity or reduce settling time.

15 ft. from gas line or overhead electric distribution line. 25 ft. from electric transmission line in excess of 50 kV. Dig safe should be contacted at least 3 days before drilling begins where subsurface utilities are already in place.

All pumps should be installed either below the frost line with a pitless adapter or in some other heated and protected sanitary location. Above-ground pumps should be installed in sheltered, dry, accessible locations and should be protected from freezing. Shallow-well pumps should be installed as near the well or water source as possible to minimize suction lift. Submersible and helical rotor pumps must be installed in the well. A deep well jet pump may be offset from the well.

Seal with neat cement grout or sand cement grout applied from the bottom of the drill hole upward to a depth which will adequately prevent subsurface leakage from the artesian zone.