16 Tex. Admin. Code § 76.100 - Technical Requirements - Locations and Standards of Completion for Wells
(a) Wells shall be completed in accordance
with the following specifications and in compliance with the local groundwater
conservation district rules or incorporated city ordinances.
(1) Siting Method. A well shall be located a
minimum horizontal distance of one hundred fifty (150) feet from any
concentrated sources of potential contamination such as, but not limited to,
existing or proposed livestock or poultry yards, cemeteries, pesticide
mixing/loading facilities, and privies, except in the case of monitoring,
dewatering, piezometer, and recovery wells which may be located where necessity
dictates. A well shall be located a minimum horizontal distance of one hundred
(100) feet from an existing or proposed septic system absorption field, septic
system spray area, a dry litter poultry facility and fifty (50) feet from any
adjacent property line provided the well is located at the minimum horizontal
distance from the sources of potential contamination.
(2) A well shall be located a minimum
horizontal distance of fifty (50) feet from any water-tight sewage and
liquid-waste collection facility except in the case of monitoring, dewatering,
piezometer, and recovery wells which may be located where necessity
dictates.
(3) A well shall be
located at a site not generally subject to flooding; provided however, that if
a well must be placed in a flood-prone area, it shall be completed with a
watertight sanitary well seal, so as to maintain a junction between the casing
and pump column, and a steel sleeve extending a minimum of thirty-six (36)
inches above ground level and twenty-four (24) inches below the ground
surface.
(4) A driller is not
required to adhere to the property line distance requirements if:
(A) the well is located within a groundwater
conservation district, and the district's rules regulate the spacing of
wells;
(B) the well is located on
property that has restrictions regulating the spacing of wells and on-site
sewage systems; or
(C) public
wastewater treatment is provided and utilized by the owner.
(b) Alternative siting
methods:
(1) Unless the well is drilled
within the Edwards Aquifer, the distances given for separation of wells from
sources of potential contamination in subsection (a)(1) may be decreased to a
minimum of fifty (50) feet provided the well is cemented with positive
displacement technique to a minimum of one hundred (100) feet to surface or the
well is tremie pressure filled to the depth of one hundred (100) feet to the
surface provided the annular space is three (3) inches larger than the outside
diameter of the casing. For wells less than one hundred (100) feet deep, the
cement slurry, bentonite grout, or bentonite column shall be placed to the top
of the production zone. In areas of shallow, unconfined groundwater aquifers,
the cement slurry, bentonite grout, or bentonite column need not be placed
below the production zone. In areas of shallow, confined groundwater aquifers
having artesian head, the cement slurry, bentonite grout, or bentonite column
need not be placed below the top of the water-bearing strata.
(2) A well that is cemented with positive
displacement technique to a minimum of one hundred (100) feet to surface or a
well that is tremie pressure filled to the depth of one hundred (100) feet to
the surface (provided the annular space is three (3) inches larger than the
outside diameter of the casing) may encroach up to five (5) feet of the
adjacent property line. For wells less than one hundred (100) feet deep, the
cement slurry, bentonite grout, or bentonite column shall be placed to the top
of the producing layer. In areas of shallow, unconfined groundwater aquifers
having artesian head, the cement slurry, bentonite grout, or bentonite column
need not be placed below the top of the water production zone.
(c) Drilling the well
(1) All wells shall be completed so that
aquifers or zones containing waters that differ in chemical quality are not
allowed to commingle in the casing, borehole annulus or the filter pack and
cause quality degradation of any aquifer or zone. When aquifers or zones of
lesser quality are overlying the production aquifer or zone, the borehole
annulus shall be pressure grouted with bentonite or cement from the top of the
production zone back to the surface unless formations make total grouting
impossible or impractical. In this case the entire borehole annulus which is
groutable shall be grouted and sealed including proper surface annular grouting
and completion.
(2) The well casing
shall be capped or completed in a manner that will prevent pollutants from
entering the well.
(3) Each
licensee shall use potable water in drilling fluids.
(4) Each licensed well driller drilling,
deepening, or altering a well shall keep any drilling fluids, tailings,
cuttings or spoils contained in such a manner so as to prevent spillage onto
any property not under the jurisdiction or control of the well owner without
the property owner's written consent.
(5) Each licensed well driller drilling,
deepening, or altering a well shall prevent the spillage of any drilling
fluids, tailings, cuttings or spoils into any body of surface water.
(6) A test well that is drilled for exploring
for groundwater shall not be open at the surface or allowing water zones of
different chemical qualities to commingle and must be completed or plugged
within six (6) months of drilling.
(7) Water wells located within public water
supply system sanitary easements must be constructed to public well standards
pursuant to 30 TAC Chapter 290.
(d) Casing the well
(1) The driller casing a well shall install a
watertight pipe, temporarily or permanently to maintain the hole sidewalls
against caving, advance the borehole, and in conjunction with cementing and/or
bentonite grouting, confine the groundwater to their respective aquifer or zone
of origin, to prevent surface contaminant infiltration.
(2) Only the following casing materials may
be used for a water well:
(A) Plastic
casing--National Sanitation Foundation (WSF-WC) or American Society of Testing
Material (ASTM) F-480 minimum SDR 26 approved water well casing;
(B) Steel casing--New ASTM A-53 Grade or
better, and have a minimum weight and thickness of American National Standards
Institute (ANSI) schedule 10; or
(C) Fiberglass Casing--National Sanitation
Foundation sixty-one (NSF-61) and American Society of Testing Material (ASTM)
D2996 approved Filament Wound fiberglass casing (Glass-Fiber-Reinforced
Thermosetting-Resin pipe.)
(D)
Monitoring wells may use other materials, such as flouropolymer (Teflon), glass
fiber reinforced epoxy, or various stainless steel alloys;
(e) Annular Seal. The annular
space to a minimum of ten (10) feet shall be three (3) inches larger in
diameter than the outside diameter of the casing and filled from ground level
to a depth of not less than ten (10) feet below the land surface or well head
with cement slurry, bentonite grout, or eight (8) feet solid column of granular
sodium bentonite topped with a two (2) foot cement atmospheric barrier, except
in the case of monitoring, dewatering, piezometer, and recovery wells when the
water to be monitored, recovered, or dewatered is located at a more shallow
depth. In that situation, the cement slurry, or bentonite column shall only
extend down to the level immediately above the monitoring, recovery or
dewatering level.
(f) Surface
Completion
(1) In all wells where plastic
casing is used, except when a steel or polyvinyl chloride (PVC) sleeve or
pitless adapter, as described in subsection (g) is used, a concrete slab or
sealing block shall be placed above the cement slurry around the well at the
ground surface.
(2) The slab or
block shall extend laterally at least two (2) feet from the well in all
directions and have a minimum thickness of four (4) inches and should be
separated from the well casing by a plastic or mastic coating or sleeve to
prevent bonding of the slab to the casing.
(3) The surface of the slab shall be sloped
to drain away from the well.
(4)
The top of the casing shall extend a minimum of twelve (12) inches above the
land surface except in the case of monitoring wells when it is impractical or
unreasonable to extend the casing above the ground. Monitoring wells shall be
placed in a waterproof vault, the rim of which extends two (2) inches above the
ground surface and a sloping cement slurry shall be placed a minimum of twelve
(12) inches from the edge of the vault and two (2) feet below the base of the
vault between the casing and the wall of the borehole to prevent surface
pollutants from entering the monitoring well. The well casing shall have a
locking cap that will prevent pollutants from entering the well. The annular
space of the monitoring well shall be sealed with an impervious bentonite or
similar material from the top of the interval to be tested to the cement slurry
below the vault of the monitoring well.
(5) The well casing of a temporary monitoring
well shall have a locking cap and the annular space shall be sealed from zero
(0) to one (1) foot below ground level with an impervious bentonite or similar
material; and after forty-eight (48) hours, the well must be completed in
accordance with this section or plugged in accordance with §
76.104.
(6) The annular space of a
closed loop geothermal well used to circulate water or other fluids shall be
backfilled to the total depth with impervious bentonite or similar material,
closed loop injection well where there is no water or only one zone of water is
encountered you may use sand, gravel or drill cuttings to back fill up to ten
(10) feet from the surface. The top ten (10) feet shall be filled with
impervious bentonite or similar materials and shall meet the standards pursuant
to Texas Commission on Environmental Quality 30 TAC Chapter 331.
(g) Alternative Surface
Completion. In wells where a steel or PVC sleeve is used:
(1) The steel sleeve shall be a minimum of
3/16 inches in thickness and shall be a minimum of twenty-four (24) inches in
length. The plastic sleeve shall be a minimum of Schedule 80 sun resistant or
SDR 17 sun resistant and be twenty-four (24) inches in length, and either
sleeve used shall extend twelve (12) inches into the cement, except when steel
casing or a pitless adapter as described in paragraph (2) is used. The casing
shall extend to a minimum of twelve (12) inches above the land surface, and the
steel/plastic sleeve's inside diameter shall be two (2) inches larger in
diameter than the outside diameter of the plastic casing being used and filled
entirely with cement; or
(2) A slab
or block as described in subsection (f) is required above the cement slurry
except when steel casing or a pitless adapter is used. Pitless adapters may be
used in such wells, provided that:
(A) the
adapter is welded to the casing or fitted with another suitably effective
seal;
(B) the annular space between
the borehole and the casing is filled with cement to a depth not less than
twenty (20) feet below the adapter connection; and
(C) in lieu of cement, the annular space may
be filled with a solid column of granular sodium bentonite to a depth of not
less than twenty (20) feet below the adapter connection.
(h) Unless waived in writing by
the landowner, a new, repaired or reconditioned well or pump installation or
repair on a well that is used to supply water for human consumption, shall be
properly disinfected.
Notes
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