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strata. Well construction materials containing more than 0.25% lead
are prohibited.
(C) The space between the casing and drill hole shall
be sealed by using enough cement under pressure to completely fill
and seal the annular space between the casing and the drill hole.
The well casing shall be cemented in this manner from the top of the
shallowest formation to be developed to the earth's surface. The driller
shall utilize a pressure cementation method in accordance with the
most current AWWA Standard for Water Wells (A100), Appendix C: Section
C.2 (Positive Displacement Exterior Method); Section C.3 (Interior
Method Without Plug); Section C.4 (Positive Placement, Interior Method,
Drillable Plug); and Section C.5 (Placement Through Float Shoe Attached
to Bottom of Casing). The grouting mixture used to pressure cement
the annular space shall be neat cement as specified in the most current
AWWA Standard for Water Wells and to which a maximum of 6%, by dry
weight, bentonite and 2%, by dry weight, calcium chloride may be added.
The minimum annular space between the outside diameter of the casing
pipe and the borehole shall be no less than 1 1/2 inches in radial
thickness or three inches in net diametrical difference and the pressure
grouting shall be from the bottom upward utilizing one of the methods
listed in this subparagraph for all public water system groundwater
well construction. Cementation methods other than those listed in
this subparagraph may be used on a site-specific basis with the prior
written approval of the executive director. A cement bonding log,
as well as any other documentation deemed necessary, may be required
by the executive director to assure complete sealing of the annular
space.
(D) When a gravel packed well is constructed, all gravel
shall be of selected and graded quality and shall be thoroughly disinfected
with a 50 mg/L chlorine solution as it is added to the well cavity.
(E) Safeguards shall be taken to prevent possible contamination
of the water or damage by trespassers following the completion of
the well and prior to installation of permanent pumping equipment.
(F) Upon well completion, or after an existing well
has been reworked, the well shall be disinfected in accordance with
current AWWA standards for well disinfection except that the disinfectant
shall remain in the well for at least six hours.
(i) Before placing the well in service, the water containing
the disinfectant shall be flushed from the well and then samples of
water shall be collected and submitted for microbiological analysis
until three successive daily raw water samples are free of coliform
organisms. The analysis of these samples must be conducted by a laboratory
accredited by the Texas Commission on Environmental Quality.
(ii) Appropriate facilities for treatment of the water
shall be provided where a satisfactory microbiological record cannot
be established after repeated disinfection. The extent of water treatment
required will be determined on the basis of geological data, well
construction features, nearby sources of contamination and, perhaps,
on the basis of quantitative microbiological analyses.
(G) A complete physical and chemical analysis of the
water produced from a new well shall be made after 36 hours of continuous
pumping at the design withdrawal rate. Shorter pump test periods can
be accepted for large capacity wells producing from areas of known
groundwater production and quality so as to prevent wasting of water.
Samples must be submitted to an accredited laboratory for chemical
analyses. Tentative approval may be given on the basis of tests performed
by in-plant or private laboratories, but final acceptance by the commission
shall be on the basis of results from the accredited laboratory. Appropriate
treatment shall be provided if the analyses reveal that the water
from the well fails to meet the water quality criteria as prescribed
by the drinking water standards. These criteria include turbidity,
color and threshold odor limitations, and excessive hydrogen sulfide,
carbon dioxide, or other constituents or minerals which make the water
undesirable or unsuited for domestic use. Additional chemical and
microbiological tests may be required after the executive director
conducts a vulnerability assessment of the well.
(H) Below ground-level pump rooms and pump pits will
not be allowed in connection with water supply installations.
(I) The well site shall be fine graded so that the
site is free from depressions, reverse grades, or areas too rough
for proper ground maintenance so as to ensure that surface water will
drain away from the well. In all cases, arrangements shall be made
to convey well pump drainage, packing gland leakage, and floor drainage
away from the wellhead. Suitable drain pipes located at the outer
edge of the concrete floor shall be provided to collect this water
and prevent its ponding or collecting around the wellhead. This wastewater
shall be disposed of in a manner that will not cause any nuisance
from mosquito breeding or stagnation. Drains shall not be directly
connected to storm or sanitary sewers.
(J) In all cases, a concrete sealing block extending
at least three feet from the well casing in all directions, with a
minimum thickness of six inches and sloped to drain away at not less
than 0.25 inches per foot shall be provided around the wellhead.
(K) Wellheads and pump bases shall be sealed by a gasket
or sealing compound and properly vented to prevent the possibility
of contaminating the well water. A well casing vent shall be provided
with an opening that is covered with 16-mesh or finer corrosion-resistant
screen, facing downward, elevated and located so as to minimize the
drawing of contaminants into the well. Wellheads and well vents shall
be at least two feet above the highest known watermark or 100-year
flood elevation, if available, or adequately protected from possible
flood damage by levees.
(L) If a well blow-off line is provided, its discharge
shall terminate in a downward direction and at a point which will
not be submerged by flood waters.
(M) A suitable sampling cock shall be provided on the
discharge pipe of each well pump prior to any treatment.
(N) Flow-measuring devices shall be provided for each
well to measure production yields and provide for the accumulation
of water production data. These devices shall be located to facilitate
daily reading.
(O) All completed well units shall be protected by
intruder-resistant fences, the gates of which are provided with locks
or shall be enclosed in locked, ventilated well houses to exclude
possible contamination or damage to the facilities by trespassers.
The gates or wellhouses shall be locked during periods of darkness
and when the plant is unattended.
(P) An all-weather access road shall be provided to
each well site.
(Q) If an air release device is provided on the discharge
piping, it shall be installed in such a manner as to preclude the
possibility of submergence or possible entrance of contaminants. In
this respect, all openings to the atmosphere shall be covered with
16-mesh or finer, corrosion-resistant screening material or an acceptable
equivalent.
(4) Pitless units may be desirable in areas subject
to vandalism or extended periods of subfreezing weather.
(A) Pitless units shall be shop fabricated from the
point of connection with the well casing to the unit cap or cover,
be threaded or welded to the well casing, be of watertight construction
throughout, and be of materials and weight at least equivalent and
compatible to the casing. The units must have a field connection to
the lateral discharge from the pitless unit of threaded, flanged,
or mechanical joint connection.
(B) The design of the pitless unit shall make provisions
for an access to disinfect the well, a properly designed casing vent,
a cover at the upper terminal of the well that will prevent the entrance
of contamination, a sealed entrance connection for electrical cable,
and at least one check valve within the well casing. The unit shall
have an inside diameter as great as that of the well casing up to
and including casing diameters of 12 inches.
(C) If the connection to the casing is by field weld,
the shop-assembled unit must be designed specifically for field welding
to the casing. The only field welding permitted will be that needed
to connect a pitless unit to the well casing.
(D) With the exception of the fact that the well was
constructed using a pitless unit, the well must otherwise meet all
of the requirements of paragraph (3) of this subsection.
(d) Springs and other water sources.
(1) Springs and other similar sources of flowing artesian
water shall be protected from potential contaminant sources in accordance
with the requirements of subsection (c)(1) of this section.
(2) Before placing the spring or similar source into
service, completion data similar to that required by subsection (c)(3)(A)
of this section must be submitted to the executive director for review
and approval to the Texas Commission on Environmental Quality, Water
Supply Division, MC 159, P.O. Box 13087, Austin, Texas 78711-3087.
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