Current through September 17, 2024
A water well contractor must verify the purpose of a new well
with the owner or the system's engineer. If the well is to serve water to the
public, see 178 NAC 12-008.
12-004.01
Construction of Potable Well:
1. A potable water well to be used for human
consumption must not be constructed as a driven sandpoint well.
2. It must meet the requirements specified in
178 NAC 12-003.
12-004.02
Casing a Potable
Well: A potable water well must be cased with unused watertight
casing in the following manner:
12-004.02A The
top of the well must extend at least 12 inches above the grade of the land
surface. The earth surrounding the well must slope away from the well and must
be firmly tamped to prevent water from seeping down the casing.
12-004.02B Non-steel cased wells must be
fitted with a watertight connection to .237 inch wall minimum steel casing
through the frost zone, unless terminating in a pump house.
12-004.02C Non-steel watertight casing must
be manufactured expressly for well casing, and must meet the following specific
requirements:
1. Casing strength must be not
less than 160 pounds per square inch or Standard Dimension Ratio (SDR)
26.
2. Plastic or other non-steel
casing must bear the National Sanitation Foundation (NSF) 61 stamp of
approval.
12-004.02D
Special Engineered (SE) plastic piping systems must meet the requirements of
178 NAC 12-004.02C item 2.
12-004.02E Packaging of thread compounds,
sealants and lubricants must bear the NSF Standard 61 stamp of
approval.
12-004.03
Potable Well Shock Decontamination
12-004.03A When a well which will produce
water for human consumption is constructed or altered, it must be
decontaminated.
12-004.03B The
water well contractor/pump installation contractor must supply the landowner
with an informational brochure that tells the owner why s/he should test
his/her water and what the results mean.
12-004.03C Shock decontamination must be
accomplished by:
1. Using a solution
equivalent to 200 parts per million chlorine (See Table 1);
2. Pouring the solution directly into the
well; splashing the well pump, piping, casing, and other well equipment as much
as possible; agitating the water in the well by surging the pump or by other
means to mix the solution with the water or recirculating the water into the
well, always washing down the casing or drop pipe;
3. Letting the mixture stand in the well for
a minimum of 4 hours;
4. Opening
all water taps and pumping the well until evidence of the solution is detected
at all taps. The system must be allowed to stand idle for a minimum of 2
additional hours and then the entire system must be flushed to waste.
12-004.04
Bored (Seep or Cistern) Wells must be constructed to
the same minimum standards for potable wells with the following exceptions:
(See Figure 3)
12-004.04A Casing materials may
be concrete, tile, or other material approved in 178 NAC 12-003.04C.
12-004.04B The annular space below the
surface seal must be filled with gravel.
12-004.04C Watertight casing and grout must
be placed from 10 feet below the surface or the static water level, whichever
is less, to the surface or the bottom of the pitless unit. (See Figure
3)
12-004.05
Open Hole Wells must be constructed to the same
minimum standards for potable wells and in the following manner. (See Figure 4)
12-004.05A
The
casing must extend at least 2 feet into the open borehole. A seal must be
created between the casing and the lower borehole to ensure that the annular
fill material remains in the upper borehole. This can be accomplished by using
a collar attached to the casing, a drive shoe, or other sealing
device.
12-004.05B A minimum 5 foot
primary aquifer seal must be placed in the annular space directly above the
collar, drive shoe, or other sealing device.
12-004.05C
Open Hole Wells in
Multiple Aquifers must be constructed to the same minimum
standards for potable wells and must comply with 178 NAC 12-004.05A and
12-004.05B. The screened section must be gravel packed. The gravel pack must
extend both above and below the screen for a length equal to 2.5 times the
diameter of the well. A 5 foot minimum primary aquifer seal must be placed
directly above the gravel pack. (See Figure 5)