Iowa Administrative Code › Agency 567 - Environmental Protection Commission › Title II - Air Quality › Division B › Chapter 49 - Nonpublic Water Supply Wells › Rule 567-49.7 - General Construction Requirements

Current through Register Vol. 47, No. 3, July 24, 2024
Wells shall be planned and constructed to adapt to the
					 geologic and groundwater conditions of the proposed well site to ensure
					 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 which is 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
				  contamination of the well. Water used for drilling shall be treated with 3
				  pints of 5.25 percent sodium hypochlorite solution per 100 gallons of water or
				  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.
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 properly screened and
				  oriented vent openings.
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 other than those used as pump house
					 floors as indicated in 49.12(2).
(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 constructed after July 1, 1986, must be
				  constructed to allow for some potential well interference.
Allowance for potential well interference is accomplished
					 by constructing a nonregulated well to anticipate a lowering of the static head
					 of the well which may be caused by interference from a nearby permitted use
					 well.
a.
The well must be drilled deep
							 enough to allow for setting the pump at least 10 feet or half the normal
							 pumping drawdown, whichever is greater, below the initial recommended setting
							 depth.
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b.
If the well draws from an
							 unconfmed aquifer, the static water level may drop to half the saturated
							 thickness of the aquifer before well interference is considered, if the
							 calculation in
"a "
above should indicate a shallower depth.
							 Shallow aquifers that are only slightly confined may be classified as unconfmed
							 aquifers for this purpose.
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c.
Where a well penetrates a confined
							 aquifer, the static water level is protected only to the top of the aquifer if
							 the calculation in
"a "
above should indicate a deeper level.
d.
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 must be constructed to accommodate a pump capable of supplying a
							 sufficient water supply at protected levels.
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The well design also needs to consider drought and reduced
					 well efficiency. (Additional information is contained in 567-Chapter
					 54.)
A well that is used to withdraw more than 25,000 gallons of
					 water per day requires a water use permit from the Iowa department of natural
					 resources. Upon obtaining such a permit, the well is called a permitted use. 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. 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). A person desiring to construct a well not requiring a water use
					 permit should first obtain information concerning nearby permitted use wells.
					 The department of natural resources will provide information on permitted use
					 wells upon request.
(4)
Access port for measurement of water levels.
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 measurement of water levels. When a spool type of pitless adapter is used
				  which 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.
There may be local confining beds
				  that serve an important protective function. Permitted use wells shall use
				  casing and grouting to maintain a hydraulic separation between distinct
				  aquifers separated by confining intervals. Extreme caution should be exercised
				  in the construction of non-permitted use wells if allowing the well to connect
				  aquifers across confining intervals, particularly in areas where that would
				  open the aquifer to surficial contamination, i.e., in areas where the upper
				  rock unit is unconfined or contains less than 40 feet of unconsolidated
				  materials. The administrative authority shall be consulted for possible local
				  regulations when interconnection of aquifers across confining intervals is
				  anticipated.