Iowa Admin. Code r. 567-49.9 - General construction requirements
Wells shall be planned and constructed to adapt to the geologic and groundwater conditions of the proposed well site to ensure both the reasonable utilization of every natural protection against contamination of the water-bearing formation(s) and the exclusion of possible sources of contamination, to attempt to produce bacterially safe water free of health-related problems.
(1)
Water used in construction. Water used in the construction
process shall be obtained from a potable water source that will not result in
well contamination. Drilling water shall be treated with 3 pints of 5.25
percent sodium hypochlorite solution per 100 gallons of water, 0.25 pounds of
65 percent calcium hypochlorite per 100 gallons of water, or other additives to
produce an equivalent concentration of chlorine residual (50 ppm).
(2)
Wellhead.
a. The upper terminal casing of all wells
shall extend at least 12 inches above established grade or pump house floor, or
the 100-year flood level, whichever is higher. A well cap or sanitary seal
shall be installed immediately following well completion. A well cap shall be
used on an exposed well; a sanitary seal only on a well terminating within a
wellhouse. Any openings in the cap or seal, such as for pump wiring or water
depth measurement, shall be properly grommeted or sealed, except for properly
screened and oriented vent openings.
b. The ground surface immediately adjacent to
the well casing shall be compacted and graded so that surface water is diverted
away from the casing. Well platforms are not recommended, except those used as
pump house floors.
(3)
Criteria for well interference protection. 567-Chapter 54
provides an administrative process for owners of nonregulated wells to receive
compensation for well interference caused by permitted uses. To be eligible for
compensation due to well interference, nonregulated wells shall be constructed
to allow for some potential well interference.
a. Allowance for potential well interference
is accomplished by constructing a nonregulated well to anticipate a lowering of
the well's static head, which may be caused by interference from a nearby
permitted use well.
(1) A well shall be
drilled deep enough to allow for pump setting at least 10 feet or half the
normal pumping drawdown, whichever is greater, below the initial recommended
setting depth.
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(2) If a well draws from an unconfined
aquifer, the static water level may drop to half the saturated thickness of the
aquifer before well interference is considered, if the calculation in (1) above
should indicate a shallower depth. Shallow aquifers that are only slightly
confined may be classified as unconfined aquifers for this purpose.
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(3) Where a well penetrates a confined
aquifer, the static water level is protected only to the top of the aquifer if
the calculation in (1) above should indicate a deeper level.
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(4) Protected levels for flowing wells will
be considered the top of the confined aquifer or 100 feet below the surface,
whichever is higher. Flowing wells shall be constructed to accommodate a pump
capable of supplying a sufficient water supply at protected levels.
(5) The well design also needs to consider
drought and reduced well efficiency. Additional information is provided in
567-Chapter 54.
b. A well
that is used to withdraw more than 25,000 gallons of water per day requires a
water use permit from the department. Upon obtaining such a permit, the well is
considered a permitted use.
(1) If a permitted
use exists prior to the construction of a well without a water use permit, no
compensation for well interference will be allowed unless a significant change
in the permitted use occurs.
(2) A
physical change to withdrawal facilities may be considered a significant change
to a permitted use (e.g., moving the withdrawal location, installing a new
well, or installing a higher capacity pump).
(3) A person desiring to construct a well not
requiring a water use permit should first obtain information concerning nearby
permitted use wells. The department shall provide information on permitted use
wells upon request.
(4)
Access port for water level
measurement. Permitted use wells shall be equipped with an access port
having a minimum diameter of ¾ inch. The access port shall be fitted
with a threaded cap or plug and be located to allow insertion of a steel tape
or electric probe into the well for water level measurements. When a spool type
of pitless adapter is used that obstructs clear access to the water, a
¾-inch pipe shall be attached to the spool and brought to the surface
below the well cap to allow water level measurements. Wells not requiring a
water use permit should be constructed with an access port for water level
measurement for possible future well interference concerns.
(5)
Interconnection of
aquifers. Permitted use wells shall use casing and grouting to
maintain a hydraulic separation between distinct aquifers separated by
confining intervals. Hydraulic separation of distinct aquifers for
non-permitted use wells is not required; however, caution should be taken to
prevent aquifer contamination, and the administrative authority shall be
consulted for possible local regulations when interconnection of aquifers
across confining intervals is anticipated.
Notes
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
All materials utilized in
(1) Water well casing.
1a. Steel well casing and couplings.
(1) Steel well casing pipe shall have the dimensions and weights specified in Table 49.9(1)"a"(4). Well casing pipe shall be new steel pipe meeting one of the following standards:
1. ASTM A 53-96,
2. ASTM A 106-95,
3. ASTM A 589-95a -Type I, II or III,
4. API 5CT (5th Edition, 4/1/95),
5. API 5D (3rd Edition, 8/1/92), or
6. API 5L (41st Edition, 4/1/95).
(Copies of these standards are available for inspection at the Des Moines office of the
(2) Each length of casing shall be legibly marked in accordance with API or ASTM marking specifications showing the manufacturer's or processor's name or trademark, size in inches, weight in pounds per foot, whether seamless or welded (type of weld) and the API or ASTM specification or trade monogram.
(3) All casing pipe joints shall be watertight welded construction or threaded couplings.
(4) Minimum casing pipe and coupling weights and dimensions are as follows:
Table 49.9(1)"a"(4)
Minimum Casing Pipe and Coupling Weights and Dimensions
| Size (inches) | Weight (lbs/ft) | Pipe | Couplings | |||||||
| Threads & Coupling | Plain End | Thickness (inches) | External Diameter (inches) | Internal Diameter (inches) | Threads per inch | External Diameter (inches) | Length (inches) | |||
| 1 | 1.70 | 1.68 | .133 | 1.315 | 1.049 | 11-1/2 | 1.576 | 2-5/8 | ||
| 1-1/4 | 2.30 | 2.27 | .140 | 1.660 | 1.380 | 11-1/2 | 1.900 | 2-3/4 | ||
| 1-1/2 | 2.75 | 2.72 | .145 | 1.900 | 1.610 | 11-1/2 | 2.200 | 2-3/4 | ||
| 2 | 3.75 | 3.65 | .154 | 2.375 | 2.067 | 11-1/2 | 2.750 | 2-7/8 | ||
| 2-1/2 | 5.90 | 5.79 | .203 | 2.875 | 2.469 | 8 | 3.250 | 3-15/16 | ||
| 3 | 7.70 | 7.58 | .216 | 3.500 | 3.068 | 8 | 4.000 | 4-1/16 | ||
| 3-1/2 | 9.25 | 9.11 | .226 | 4.000 | 3.548 | 8 | 4.625 | 4-3/16 | ||
| 4 | 11.00 | 10.79 | .237 | 4.500 | 4.026 | 8 | 5.200 | 4-5/16 | ||
| 5 | 15.00 | 14.62 | .258 | 5.563 | 5.047 | 8 | 6.296 | 4-1/2 | ||
| 6 | 19.46 | 18.97 | .280 | 6.625 | 6.065 | 8 | 7.390 | 4-11/16 | ||
| 6-5/8 OD | 20.00 | 19.49 | .288 | 6.625 | 6.049 | 8 | 7.390 | 4-11/16 | ||
| 7 0D | 20.00 | 19.54 | .272 | 7.000 | 6.366 | 8R | 7.657 | 4-11/16 | ||
| 8 | 29.35 | 28.55 | .322 | 8.625 | 8.071 | 8 | 9.625 | 5-1/16 | ||
| 10 | 41.85 | 40.48 | .365 | 10.750 | 10.136 | 8 | 11.750 | 5-9/16 | ||
| 12 | 51.15 | 49.56 | .375 | 12.750 | 12.090 | 8 | 14.000 | 5-15/16 | ||
| 14 OD | 57.00 | 54.57 | .375 | 14.000 | 13.250 | 8 | 15.000 | 6-3/8 | ||
| 16 OD | 65.30 | 62.58 | .375 | 16.000 | 15.250 | 8 | 17.000 | 6-3/4 | ||
| 18 OD | 73.00 | 70.59 | .375 | 18.000 | 17.250 | 8 | 19.000 | 7-1/8 | ||
| 20 OD | 81.00 | 78.60 | .375 | 20.000 | 19.250 | 8 | 21.000 | 7-5/8 | ||
R = Round Threads
b. Thermoplastic casing and couplings.
(1) Materials. Thermoplastic well casing pipe and couplings shall be new polyvinyl chloride (PVC) or acrylonitrile-butadiene-styrene (ABS) material produced to and meeting the ASTM F 480 standard and shall have a standard dimension ratio (SDR) of 21, 17, or 13.5, a dimension ratio (DR) of 18 or 14, or a schedule 40 or 80 rating depending upon the specification. Styrene-rubber thermoplastic well casing pipe, including ASTM F 480, may not be used.
(2) Potable water standards. The thermoplastic well casing pipe, pipe couplings, cement, primer and other components used shall be approved for well casing pipe in potable water supplies by the NSF Standard Number 61 or the health effects portion of Standard Number 14 as they relate to well casing pipe, or an approved equivalent organization.
(3) Markings. Each length of casing shall be legibly marked showing the manufacturer's or processor's name or trademark, size in inches, and the ASTM F 480 specification or trade monogram.
(4) Casing joints. The thermoplastic pipe shall be assembled with either flush-threaded joints, integral-bell, solvent-cemented joints, one-piece solvent-cemented couplings or nonmetallic restrained joint system in a manner according to the specifications in ASTM F 480.
(5) Hydraulic collapse pressure for plastic casing. The following table provides specifications for maximum hydraulic collapse pressure (in feet of water head) to which PVC well casing of different strengths can be installed.
Table 49.9(1)"b"(5)
PVC
| Maximum Hydraulic Loading (in feet of water head) (1) | |||||||||
| ASTM F 480 or ASTM 2241 | C-900 | ASTM 1785 | |||||||
| SDR | SDR | SDR | DR | DR | SCH. | SCH. | |||
| SIZE | 21 | 17 | 13.5 | 18 | 14 | 40 | 80 | ||
| 4" | 257' | 496' | 1,024' | - | - | 353' | 1,055' | ||
| 41/2" | 257' | 496' | 1,024' | - | - | - | - | ||
| 5" | 257' | 496' | 1,024' | - | - | 236' | 758' | ||
| 6" | 257' | 496' | 1,024' | 490' | 956' | 177' | 678' | ||
| 8" | 257' | 496' | 1,024' | 490' | 956' | 121' | 471' | ||
| 10" | 257' | 496' | 1,024' | 490' | 956' | 90' | 404' | ||
| 12" | 257' | 496' | 1,024' | 490' | 956' | 74' | 376' | ||
| 16" | 257' | 496' | 1,024' | 490' | 956' | 70' | 350' | ||
(1) Determined by formulae in ASTM F 480 with Poisson's ratio of.38
(6) When cement grout is used with thermoplastic casing, the manufacturer's specifications for use shall be followed except in the top 40 feet.
(7) Thermoplastic pipe extending above ground shall be protected from ultraviolet light exposure.
(8) Under no circumstances shall thermoplastic water well casing be driven.
(2) Grouting guides. Casing that is to be grouted shall have a minimum of two sets of centering guides attached to the casing so as to permit the unobstructed flow and deposition of grout .
(3) Grouting. Materials and procedures for grouting shall be as follows:
a. Concrete grout . The mixture, used with bored and augered wells, shall consist of cement, sand aggregate and water, in the proportion of one bag cement (94 lbs.) and an equal volume of aggregate to not more than six gallons of clean water. Concrete grout shall not be used below the water table. Admixtures to reduce permeability or control setting time must meet ASTM Standard C 494-92. Concrete grout may be used with permission of the administrative authority where large void spaces need to be filled.
b. Neat cement grout . The mixture shall consist of one bag of cement (94 lbs.) to not more than six gallons of clean water. Admixtures to reduce permeability or control setting time must meet ASTM Standard C 494-92.
c. Bentonite grout . This is a mixture of water and commercial sodium-bentonite clay manufactured for the purpose of water well grouting. Mixing shall be per manufacturer's specifications. Sodium-bentonite mixtures that have high viscosity but contain less than 10 percent solids are designed for drilling purposes and shall not be used as grout . Organic polymers used in grout mixtures must meet NSF Standard 60.
d. Exclusion. Drilling fluids and cuttings may not be used as grouting material to satisfy the minimum grouting requirements.
e. Application. Grouting shall be performed by pumping the mixture into the annular space from the bottom upward through the casing or through a tremie pipe until the annular space is filled. Grouting shall be done in one continuous operation, if possible. The bottom of the tremie pipe must remain submerged in grout while grouting.
f. Exceptions. The exceptions to this method of application are the use of buried-slab, percussion, or casing-hammer/rotary methods to construct a well . The proper grouting methods for these types of wells are specified in 49.8(1) and 49.8(2). Another exception is where dry bentonite is required because circulation cannot be maintained as described in 49.8(1)"b"(5).
(4) Pitless adapters andpitless units. Rescinded IAB 7/21/04, effective 8/25/04.
1 Effective date of 49.9(1)"a" delayed 70 days by the Administrative Rules Review Committee at its meeting held May 12, 1998.