| (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-53Grade 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.
Cont'd... |
