Wells and Borings Approved Products and Materials

Minnesota Rules, part 4725.5350 requires that a buried or partially buried pressure tank installed on a water-supply well must:

• Be identified with the manufacturer's name, a serial number, the allowable working pressure, and the year fabricated;
• Have an interior coating that complies with ANSI/NSF Standard 61-2003e if the tank has an interior coating in contact with water;
• Have a minimum one-fourth inch wall thickness for a steel pitless adapter tank attached directly to the well casing;
• Have all connections to the pressure tank welded or threaded; and
• Be installed above the water table.

Following is a partial list of requirements for drilling fluids and grouts used in wells and borings in Minnesota (complete requirements can be found in Minnesota Rules, chapter 4725, Wells and Borings):

• Drilling fluid additives, including bentonite, must meet the requirements of ANSI/NSF Standard 60-2003e.
• Bentonite used for grout must meet ANSI/NSF Standard 60, or be a natural bentonite without additives.
• Grout must be mixed into a water slurry and pumped through a tremie pipe or the casing.
• Bentonite pellets, chips, and dry granular bentonite may be used only as an intermediate seal between a gravel pack and grout in any regulated well or boring. The layer of bentonite pellets, bentonite chips, or granular bentonite must not exceed 5 feet in thickness, must not extend into a confining layer, and must not extend more than 10 feet above the static water level.

Minnesota Rules, part 4725.4850 requires that a pitless adapter or pitless unit must:

• Be constructed to provide complete clearance within the internal diameter of the casing;
• Be designed to be field-welded by holding the welding rod in a vertical or horizontal position, or bench-welded before field installation with a material as corrosion-resistant as the parent material;
• Have all threaded joints watertight with no threads exposed;
• Impart no taste, odor, or toxic material to the water; and
• Connect to the casing by a threaded connection, welded connection, bolted flange with gasket, clamp and gasket, or compression gasket.

Environmental wells and dewatering wells may be completed at-grade only on a roadway, sidewalk, driveway, or a parking area, and only if there is no location that would allow for termination of the well casing at least 12 inches above the established ground surface. A well that is completed at-grade must comply with Minnesota Rules, part 4725.6850, which requires that:

• The location of the well identified by unique well number must be marked on a scaled map with angles and directions from surveyed property corners, a permanent benchmark, or the corners of a permanent structure. The map must be submitted to the commissioner with the well record.
• At-grade well casing must terminate no lower than the established ground surface.
• The well must be contained in a protective manhole cover or vault. The top of the manhole cover or vault must be no less than two inches above the established ground surface.
• The established ground surface must be sloped to divert surface water or spills away from the well and to allow for traffic movement and snow plowing.
• The manhole cover or vault must be installed in a concrete pad at least four inches in thickness and four feet square or four feet in diameter and of sufficient load-bearing capacity to support vehicular traffic.
• The manhole cover or vault must be labeled with the words "Monitoring Well" cast or stamped in letters at least one centimeter or one-half inch in height.
• All materials used to construct the manhole cover or vault must be resistant and impervious to water, petroleum products, and chemicals likely to be present.
• The manhole cover or vault must have a watertight, impervious compression O-ring or gasket.
• The manhole cover or vault must meet AASHTO Standards H20-44 and M306-04.
• The well casing must be secured with a locking cap or cover according to part 4725.2250, subpart 17. The manhole cover or vault must be secured with a lock or tamper-resistant bolts.
• The well label must be placed on the well casing, manhole cover, or vault, or the unique well number may be stamped on the vault.

Socket x internal (female) thread fittings meeting the requirements of ASTM D2466-02: Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 40 may be used to attach a threaded pitless unit to a 6-inch diameter PVC well casing. The fitting is to be threaded to the pitless unit and joined to the PVC well casing by solvent welding. Fittings meeting the ASTM D2466-02 requirements can be recognized using the following criteria:

1. Fitting must meet the following dimensional requirements for 6-inch nominal pipe size: the socket entrance diameter is 6.647 +_ 0.011 inches, socket bottom diameter is 6.614 +_ 0.011 inches, minimum inside diameter is 5.986 inches, minimum socket wall thickness is 0.280 inches, and minimum socket depth is 3.000 inches.
2. Fitting must be marked with the manufacturer’s name or trademark, material designation (usually PVC I), size (6"), the designation number “D2466,” and the seal or mark of the laboratory evaluating this product for potable use (this will almost always be the “NSF-PW” marking).

Other markings which may be present include the “SCH 40” designation and “435-060,” a commonly used industry part number. Fittings with these numbers are not approved unless they also have all of the markings specified in Item 2 above.

Prior to this policy change, only fittings meeting the ASTM F480-02: Standard Specification for Thermoplastic Well Casing Pipe and Couplings made in Standard Dimension Ratios (SDR), SCH 40 and SCH 80, or meeting the dimensional requirements of ASTM F480-02 were approved. Unfortunately, there are currently no fittings available for 6-inch diameter PVC well casing that meet those dimensional requirements. Industry representatives have advised the Minnesota Department of Health (MDH) that demand is not sufficient to justify the costs of manufacturing such fittings, so there are none being made now nor likely to be made for the foreseeable future.

The main difference between the two standards, with regard to the 6-inch fittings, is that the minimum socket depth for the ASTM F480-02 coupling is 3.500 inches, compared to 3.000 inches for the ASTM D2466-02 fitting. The shorter socket depth for the ASTM D2466-02 fitting leaves less room for error in assembly, but MDH Well Management staff concluded that a watertight, reliable joint could be made if good and careful workmanship is employed. Contractors are reminded that Minnesota Rules, part 4725.2650, subpart 2 requires that, when cutting plastic casing, casing ends must be cut square using fine-tooth blades with little or no set or a plastic pipe cutter equipped with extra wide rollers and thin cutting wheels.

Please note that only socket x internal (female) thread fittings are approved. Socket x external (male) thread fittings are not approved for use with 6-inch PVC well casing, and must not be used. The threaded portion of the 6-inch socket x external threaded fitting has an inside diameter of less than 6 inches, so protrudes inside the casing. This protrusion may make it difficult to install and remove pumps and screens.

Note:Taken from Memorandum dated 5/28/2014, sent to Minnesota licensed well contractors from MDH Well Management Section.

Minnesota Rules, chapter 4725 currently requires that fittings and couplings used with plastic well casing must:

1. Meet the socket dimension requirements of ASTM Standard F480-02, Table 3 and have a water pressure rating of at least 200 psi;
2. Be Schedule 40, slip x internal thread fittings, four-inch and smaller meeting the requirements of ASTM D2466-02;
3. Be Schedule 40, slip x internal thread fittings and slip x external thread fittings, five-inch diameter meeting the requirements of ASTM D2466-02; or
4. Be flush-threaded joints meeting ASTM F480-02 (monitoring wells and environmental bore holes only).

The fittings and couplings must also conform to the requirements of ANSI/NSF Standard 61-2003e or the health effects portion of ANSI/NSF Standard 14-2003.

The following links provide information about fittings and couplings that comply with the rule requirements, as well additional fittings and couplings approved for use with 6-inch diameter PVC well casing and for screen connections to PVC well casing.

• PVC Couplings and Fittings Approved for Use With PVC Well Casing (PDF)

Effective May 12, 2011, the Minnesota Department of Health Well Management Section adopted a policy allowing some alternatives to the connections currently required in rule.

Minnesota Rules, chapter 4725 currently requires that if a screen is attached or connected to plastic casing, the connection must be made by:

1. a nontoxic packer (for example, a neoprene rubber “figure K” packer);
2. a plastic coupling meeting the dimension requirements of ASTM Standard F480-02 (these couplings are not commonly available);
3. flush-threaded joints meeting ASTM F480-02 (monitoring wells and environmental bore holes only); or
4. a slip x-thread fitting meeting ASTM D2466-02 (for 4-inch and 5-inch diameter wells, only).

The rules do not require a connection between a screen and casing. For example, a telescoped screen can be installed inside a casing with no packer or other physical connection between the casing and screen.

For all practical purposes, the rules would allow only a telescoped screen (with or without a packer) for plastic well casing 6-inches or larger in diameter because there are no commonly available couplings that meet the requirements for joining a pipe size screen to plastic casing 6-inches or larger in diameter.

In order to provide well contractors with workable options for construction of plastic cased wells 6-inches in diameter and larger, with pipe size screens, the MDH has adopted the following policy:

• The requirements of Minnesota Rules, part 4725.2550, subparts 1 and 2 for compliance with a particular ASTM standard or dimensions are waived for the screen connection to 6-inch and larger diameter plastic casings.
• Plastic parts and related joining materials including solvent cements must comply with Minnesota Rules, part 4725.2550, subpart 3, which requires NSF compliance.
• If a screen is attached or connected to the casing, the connection must be made by a threaded, solvent-welded, or welded joint or by a nontoxic packer (without requiring that the coupling or fitting meet any particular standard or dimensions). For PVC well casing, only a solvent-welded plastic coupling or fitting or nontoxic packer would be acceptable. The plastic coupling or fitting may connect to the screen with threads or a solvent weld.
• Screws must not be used to join PVC casing (including joining casing to screen).

Please note that this policy does not modify the requirement that flush-threaded PVC casing may be used only in the construction of a monitoring well or environmental bore hole, and flush threaded PVC casing must meet the requirements of Minnesota Rules, part 4725.6650.

Minnesota Rules, chapter 4725, as amended on August 4, 2008, requires that any chemical placed in a well or boring to increase the yield, remove or treat contaminants or objectionable tastes or odors, or rehabilitate the well or boring must meet the requirements of ANSI/NSF Standard 60-2003e. In addition, sodium or calcium hypochlorite would be allowed if registered by the United States Environmental Protection Agency in accordance with the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), section 3(c)(7)(A) as an antimicrobial pesticide for use in potable water.