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Safe, potable ground water is one of our most precious natural resources. It can be contaminated and made dangerous, even totally useless for drinking, by improper well drilling and pump installation practices.
To guide well drillers and homeowners in the construction of safe, usable wells, the Indiana State Department of Health offers the following standards for construction of wells and installation of pumps and appurtenances. Whenever a well is opened for repair, the work and materials used should also comply with these standards. Dewatering wells, irrigation wells, heating and cooling supply and return wells, temporary service wells, construction water wells, process wells, and other structures for withdrawing ground water or lowering of a water table, regardless of location, length of intended service, or original use or intent, should be constructed in accordance with these standards. Where possible, existing wells and water systems should be upgraded to meet these standards. See the end of this monograph for definitions of the terms used herein.
Private water supply wells should be located:
Private water supply wells and buried suction pipes serving a residence should be installed the following minimum separation distances from potential sources of contamination:
|Sources of Contamination||Distance|
|* If the well casing terminates less than 25 feet from finished grade, or if the well penetrates creviced or highly porous formations, at a minimum, the distances listed in Table 1 should be doubled.|
|Independent clear water drain; septic system perimeter drain; rainwater downspout; cistern; hydrant drain; or building foundation drain||10 feet|
|Property lines||15 feet|
|Stream; lake or pond shoreline; below-ground swimming pool; open ditch or other waterway; sanitary or storm sewer constructed of water works grade ductile iron, cast iron or PVC pipe with mechanical or push-on joints||20 feet|
|Watertight grease basin; septic tank; wastewater holding tank; absorption field; constructed wetland; sewage lift station; or sanitary vault privy (a privy that utilizes a solid wall wastewater holding tank)||50 feet|
|Stable; animal barn or feeding pen; milkhouse; livestock run; or silo||50 feet|
|Sanitary or storm sewer not constructed of water works grade ductile iron, cast iron or PVC pipe with mechanical or push-on joints||50 feet|
|Pit privy (a privy that has brick-, block-, or stone-lined pit walls); manure pile; manure holding tank; silage pit; dry well; seepage pit or trench; or cesspool||100 feet|
|Surface or subsurface stored chemicals such as gasoline, diesel fuel, home heating oil, fertilizer, pesticides, etc.||100 feet|
|Septage or treated sludge disposal area; wastewater absorption; storage, retention or treatment pond; ridge and furrow waste disposal site; or spray irrigation waste disposal site||500 feet|
|Uncovered salt storage||1,500 feet|
If the residence is located within 2,500 feet of a sanitary landfill, the Office of Land Quality of the Indiana Department of Environmental Management should first be consulted for recommendations on separation from the facility.
If the distances enumerated in Table 1 cannot be met, consult with your local health department about the potential for lesser separations based on special construction or favorable geology.
A well should be located so the centerline of its casing extends at least 5 feet clear of any projection from the building. A well should be reasonably accessible for servicing and maintenance utilizing equipment for cleaning, treatment, repair, testing, or inspection. Except for well houses specifically constructed for the purpose, it is totally unacceptable to locate a well in a building or in the basement of a building.
|Nominal Size in Inches||External Diameter in Inches||Internal Diameter in Inches||Wall Thickness in Inches||Weight in Pounds / Foot - Plain Ends||Weight in Pounds / Foot - Treaded Ends|
|1Standard line pipe in these thicknesses may be threaded and coupled, or welded.|
|Nominal Size in Inches||External Diameter in Inches||Internal Diameter in Inches||Wall Thickness in Inches||Weight in Pounds / Foot - Plain Ends|
|2Lighter weight pipe, meeting ASTM Standards A-53 or A-120 and API Standard API-5L, is suitable for welding only.|
|Nominal Pipe Size||Average Outside Diameter Tolerance in Inches||On Average Outside Diameter Tolerance in Inches||Out-of-Roundness Tolerance for SDR-26 and SDR-21||Out-of-Roundness Tolerance for SDR-17 and SDR-13.5|
|Minimum Thickness1||Minimum Tolerance2|
|1The listed dimension is the lowest acceptable wall thickness at any cross section of the casing pipe|
2Thermoplastic casing can only exceed the minimum thickness by the listed amount
3Meets or exceeds Schedule 40
4Meets or exceeds Schedule 80
Nominal Pipe Size
Nominal Pipe Size
Nominal Pipe Size
Nominal Pipe Size
The annular space between the well casing and the bore hole must be properly sealed with neat cement grout or bentonite clay grout, to prevent the entry of contaminants into the aquifer.
Wells drawing from unconsolidated water-bearing formations should be fitted with screens having the maximum open area consistent with strength of the screen and the size of materials in the water-bearing formation or gravel pack. The openings should permit maximum transmissivity without clogging or jamming. Recommended screen materials include stainless steel, fiberglass, PVC, and ABS. Slotted pipe or iron or mild steel screens are unacceptable. To prevent deposition in and around screen openings, the well screen should have a total opening area sufficient to allow water entry through the screen at a maximum velocity of 0.1 feet per second.
A temporary cap should be placed on a well until pumping equipment can be installed, to prevent insects, rodents and other contaminants from entering the casing.
Each drilled well should be tested for plumbness and alignment. The bore of the hole should be sufficiently plumb and straight that the casing will not bind as it is installed. The casing should be sufficiently plumb and straight that it will not interfere with installation and operation of the pump.
Water used in drilling should be potable, so that the well and water bearing formations penetrated do not become contaminated. Water from creeks and ponds is unacceptable. As an added precaution, water used during drilling should be treated to maintain a free chlorine residual of 100 milligrams per liter (mg/l).
The well driller should furnish the owner with a duplicate copy of the information he or she is required to submit to the Indiana Department of Natural Resources in accordance with Rule 312 IAC 13-2-6, including:
No well or well-like structure may be used for the disposal of sewage, waste, or drainage or other material that might contaminate potable water. All disposal wells must be approved by the Indiana Department of Environmental Management prior to construction.
If a well is to be used to return uncontaminated water to an aquifer, the return water must not be aerated. It is important to minimize other adverse changes in return water quality, as compared to natural groundwater quality. The return pipe should discharge at least 5 feet below static water level in the return well. The screen of a recharge well should have two to three times the open area that would be provided for a comparable supply well.
If a well is to be abandoned, it must be properly sealed to restore, as far as possible, the hydrologic conditions that existed before the well was drilled. An improperly abandoned well is an uncontrolled invasion point for contaminated water. Unsealed wells are a hazard to public health, safety, welfare, and to the preservation of our groundwater resource. Sealing of wells presents a number of problems, dependant on construction of the well, the geological formations it penetrates, and hydrologic conditions. A properly sealed water well will: (1) eliminate the physical hazard; (2) prevent groundwater contamination; 3) conserve the aquifer's yield; 4) maintain the aquifer's hydrostatic head; and (5) prevent intermingling of waters when more than one aquifer is involved. The Indiana Department of Natural Resources addresses proper well abandonment in its Rule 312 IAC 13-10.
Every pump and water system should:
Well casings and pitless adapters should terminate a minimum of 12 inches above the finished grade, and at least 24 inches above maximum flood level as determined by the Indiana Department of Natural Resources. Well casings should not be cut off below ground level except to install a pitless adapter.
Pitless adapters are designed to replace the upper section of a well casing, thus serving as the terminus of the well. They are designed to be field attached to the well casing, and the discharge piping that connects to the side of the pitless adapter is designed to be pressurized by the water system at all times. The cap, casing cover or sanitary seal should be self-draining and overlap the top of the pitless adapter casing with a downward flange. There should be no openings in the pitless adapter cap, within the diameter of the pitless casing except for a factory-installed vent. Pitless adapter vents should comply with the Section 4.8.
A vertical turbine well pump should be mounted on the well casing, a pump foundation, or a pump stand, to provide an effective well seal at the top of the well. Further, the pump should be mounted on a base plate or foundation in a manner that will prevent dust and insects from entering the well.
Submersible pumps should have at least one check valve located in the discharge pump column pipe from the pump, inside the well casing. Therefore, a check valve is not needed on the piping between the well and the pressure tank. A watertight expanding gasket or equivalent well seal should be provided to seal inside the well casing and around the discharge pipe and conduit containing the power cable for the pump.
Unless the pump is submersible it should be installed at a weatherproof, frost-proof location. Pump controls should be similarly located. Any protective structure should permit removal of the pump and column pipe for maintenance and repair. The pumphouse floor should be constructed of impervious material, and slope away from the well in all directions.
All water system components, especially water lines, should be protected from freezing. Based upon past history, water lines in Indiana should be buried at the following minimum depths to preclude freezing (measured in inches from the top of pipe to finished grade):
|County||Bury Depth||County||Bury Depth||County||Bury Depth|
Vent piping should be sized to allow rapid equalization of air pressure in the well. A minimum of ½-inch piping should be utilized. Vent openings should terminate at least 12 inches above finished grade; be turned down; be secured in position; be reasonably tamper-proof; and be screened with not less than a 24-mesh screen or else filtered in a manner that will prevent the entry of insects. Pay particular attention to venting of wells in areas where toxic or flammable gases are known to be a characteristic of the water. In such cases, all vents should discharge outside at a height where the gases will not accumulate or otherwise pose a hazard.
Pumps should be of a type that use water for lubrication of the pump bearings. If a storage tank is required for lubrication water, it should be designed to protect the water from contamination. Oil lubricated line shaft turbine pumps are not acceptable for use in potable water systems.
A water system should include a sampling faucet for collection of water samples, installed on the discharge piping from the pump, prior to chlorination or any other treatment. The sampling faucets should be a minimum of ½-inch I.P.S., have a smooth end, and a turned-down nozzle. Hose bibs are unacceptable, because their threaded nozzles prevent collection of representative bacteriological samples.
All buried suction pipes should be enclosed in conduit having a minimum wall thickness equivalent to a well casing of the same size, and the annular space should be constantly subjected to water system pressure. Buried suction pipes should be located in accordance with Section 1.2. Suction pipes should never be located under a sewer.
Offset pumps and pressure tanks should be located where they are readily accessible. They should not be located in a crawl space unless the crawl space is drained to the ground surface beyond the crawl space, preferably by gravity (rather than by use of a sump pump). There should be a minimum of 4 feet clearance between the floor of a crawl space and the floor joist overhead, to allow for servicing. Pumps and pressure tanks should be located within 5 feet of the crawl space entry. The crawl space access opening should be at least 2 feet high and 2 feet wide.
No material should be used in the well or pump installation that could contaminate the aquifer or the water produced, or cause an objectionable taste or odor.
During normal operation no chemical other than sodium hypochlorite should be fed into a well. If the water pumped from a well must be chemically treated, it must be accomplished in a manner that will prevent accidental backfeed or back siphonage of the treatment chemical into the well.
The contractor is responsible for properly disinfecting any new well or well subjected to repairs or pump maintenance, upon completion of the work. Likewise, a pump installer must disinfect the well after the pump is installed, or repaired. Sufficient chlorine solution should be introduced into the well and water system to insure a minimum dosage of 100 mg/l. This chlorine solution should remain in the well and water system for a minimum of 24 hours. However, after 24 hours at least 25 mg/l of chlorine should still remain in the water. Under these conditions the well need not be disinfected again until the pump is set.
CAUTION: When working with chlorine, a person should be in a well-ventilated place. Chlorine powder or liquid should not come in contact with the skin or clothing. Chlorine solutions are best handled in wood, plastic or crockery containers because metal containers will corrode.
Every new, modified or reconditioned water source, including pumping equipment and the gravel used in gravel wall wells, should be similarly disinfected before the well is again placed into service. Such treatment should be performed when the well work is finished and again when the pump is installed or reinstalled.
|Diameter of Well Casing in inches||Gallons per foot|
After pumping the well and water system to remove the disinfectant, collect a water sample from the system using a sterile bottle provided by a laboratory that is certified to perform bacteriological analyses. Before the installation can be placed in service for human consumption, the water sample collected should have less than two coliform organisms per 100 milliliters of water. If the first sample is unsatisfactory, the disinfection procedure should be repeated and another sample collected for analysis. This procedure should continue until test results are satisfactory.
In addition to bacteriological testing, all new wells should be sampled for chemical analysis. The analysis should include all parameters listed in Table 7 below:
|Test Parameter||State/Federal Drinking Water Standard||Aesthetic Recommendation|
|* Only one test needs to be performed for nitrates. However, a laboratory can report the results of its nitrate testing in either of the ways listed.|
|Total hardness, as CaCO3||----||----|
|Specific conductance, in mhos||----||----|
|Alkalinity (Total) as CaCO3||----||----|
|Chlorides, as CI||----||250 mg/l|
|Dissolved solids||----||500 mg/l|
|Iron, as Fe (Total)||----||0.3 mg/l|
|Manganese, as Mn (Total)||----||0.05 mg/|
|Nitrates, expressed as Nitrogen *||10 mg/l||----|
|Nitrates, expressed as Nitrates *||45 mg/l||----|
|Fluoride||4 mg/l||1 mg/l|
If a resident has been advised by a physician to limit their dietary intake of sodium it is recommended that the water also be tested for sodium, so that source of sodium intake can be factored into the resident's total diet. If a water softener will be installed for treatment, then that source of sodium input to the water should also be factored into the resident's total diet. It also is desirable to test in the field for hydrogen sulfide.
It is the well owner's responsibility to obtain the required samples and have the laboratory tests made. Copies of the bacteriological and chemical analysis reports should be filed by with the Indiana Department of Natural Resources.
The well driller and/or water system installation contractor should construct and install the well and/or water system in accordance with these standards and acceptable industry practices. If these criteria are met, the well driller and water system installation contractor should not be responsible for the quality or quantity of water obtained.
Several local health departments now require that a permit be obtained before construction of a residential water supply well or installation of a well pump.
If there are special conditions that make it impossible or impractical to comply with these recommendations, your local health department should be consulted for assistance in determining safe alternatives.
"Annular space" means the space between two concentric cylinders, such as the space between the bore hole and the well casing. Annular space is usually expressed as a measurement of the difference in radii of the two cylinders.
"Aquifer" means a formation, or formations, that contains saturated permeable material that will yield water to a well.
"Casing" means pipe installed to prevent unwanted solids or liquids from entering the interior of a well.
"Contamination" means the alteration of biological, chemical, or physical properties of water so as to render the water detrimental, injurious, or harmful to health.
"Drawdown" means the difference between the static water level and the pumping water level in a well, commonly expressed in feet.
"Drive pipe" means casing driven into a hole of slightly smaller diameter than the outside diameter of the pipe.
"Groundwater" means that part of sub-surface water which is in the zone of saturation; any water below the water table.
"Pitless adapter" means a watertight unit designed and constructed for permanent attachment to the well casing. A pitless adapter provides a vent, electrical, and discharge pipe connections while preventing contaminants at or near the surface from entering the well. It also permits termination of the well above the ground surface.
"Potable water" means water acceptable for drinking under prevailing government standards.
"Pumping water level" means the level of the water in a well when it is being pumped.
"Static water level" means the level of the water in a well, when no water is being pumped or flows therefrom.
"Well seal" means a removable device used to keep the top of a well casing watertight while permitting penetration of piping, vents and electrical wiring.
"Well vent" means an opening at the top of the well casing that maintains air pressure in the well at atmospheric.
"Yield" means the quantity of water produced from the well per unit of time.