Where a potable public water supply is not available
individual sources of potable water supply shall be utilized.
Dependent upon geological and soil condition
and the amount of rainfall, individual water supplies are of the following
types: drilled well, driven well, dug well, bored well, spring, stream
or cistern. Because of the danger of contamination, surface bodies
of water and land cisterns shall not be used as sources of individual
water supply, unless properly treated by acceptable means.
An individual water supply shall be so located
and constructed as to be safeguarded against contamination.
A. Well locations.
(1) No potable ground water source or pump suction line
shall be located closer to potential sources of contamination than
the distances shown in Table 860-187A, "Distances From Source of Contamination
to Individual Water Supplies and Pump Suction Lines."
(2) In the event the underlying rock structure is limestone
or fragmented shale, the local or State Health Department shall be
consulted on well site location.
(3) Wells in residential areas shall be located so as
to anticipate the effect of new construction on the safety of the
water supply. Wherever possible, however, a community public water
system should be installed.
|
Table 860-187A
Distances from Source of Contamination
to Individual Water Supplies and Pump Suction Lines
|
---|
|
Source of Contamination
|
Distance1
(feet)
|
---|
|
Sewer
|
50
|
|
Septic tank
|
50
|
|
Subsurface pits
|
50
|
|
Pressure
|
100
|
|
Sewer of cast iron (lead joints) or approved
alternate
|
10
|
|
Subsurface disposal fields
|
2100
|
|
Seepage pits
|
100
|
|
Cesspools
|
150
|
|
Barnyards
|
100
|
|
Farm silo
|
25
|
|
Pumphouse floor drain of cast iron draining
to ground surface
|
|
|
NOTES:
|
---|
|
1.
|
These distances constitute minimum separation
and shall be in areas of crevice rock or limestone, or where the direction
of movement of the ground water is from sources of contamination toward
the well.
|
|
2.
|
When approved by the authority having jurisdiction,
and under special soil conditions this distance may be reduced. However,
a minimum separation of not less than 50 feet shall be maintained.
|
B. Elevation. Well sites shall be positively drained
and should be at higher elevations than potential sources of contamination.
C. Depth. Individual potable well supplies shall not
be developed from a water table located less than 10 feet below the
ground surface and not less than 20 feet is preferable.
D. Casings.
(1) Watertight casings. Each well shall be provided with
a watertight casing to a distance of at least 10 feet below the ground
surface. All casings shall extend at least six inches above the well
platform. The casing shall be large enough to permit installation
of a separate drop pipe. Casings should, preferably, be sealed at
the bottom in an impermeable stratum or extended several feet into
the water-bearing stratum.
(2) Drilled or driven well casings. Drilled or driven
well casings shall be of steel, wrought iron, or other suitable material.
Where drilled wells extend into a rock formation, the well casing
shall extend to and set firmly in the formation. The annular space
between the earth and the outside of the casing shall be filled with
cement grout to a distance of at least 10 feet below the ground surface.
In an instance of casing-to-rock installation, the grout shall extend
to the rock surface.
(3) Dug or bored well casings. Dug or bored well casings
shall be of watertight concrete, or other impervious material, to
a distance of at least 10 feet below the ground surface. Where the
water table is more than 10 feet below the ground surface, the watertight
casing should extend below the water table surface. Well casings for
dug or bored wells may be built of section of concrete, tile, galvanized
or corrugated metal pipe. When used, these should be surrounded by
six inches of grout poured into the hole between the outside of the
casing and the ground to a depth of at least 10 feet.
E. Cover.
(1) Every potable water well shall be equipped with an
overlapping watertight cover at the top of the casing wall or pipe
sleeve so that contaminated water or other substances cannot enter
the well through the annular opening at the top of the well casing,
wall or pipe sleeve. Covers shall extend downward at least two inches
over the outside of the well casing or wall.
(2) A dug well cover shall be provided with a pipe sleeve
which will permit the withdrawal of the pump suction pipe, cylinder
or jet body without disturbing the cover.
(3) Where pump suction or discharge pipe enter or leave
a well through the side of the casing the circle of contact shall
be water tight.
F. Drainage. All potable water well and springs shall
be constructed so that surface drainage will be diverted away from
the well or spring.