1. (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. (1) The annular space to a minimum of ten (10) feet shall be three (3) inches larger in diameter than 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. Unless the well is drilled within the Edwards Aquifer, the distances given for separation of wells from sources of potential contamination in paragraph (2) 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 pressured filled to the depth of one hundred (100) feet to the surface provided the annular space is three inches larger than 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 producing layer. 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. (2) A 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 casing may encroach up to five (5) feet of the 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, 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.
   3. (3) 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.
   4. (4) Except as noted in paragraphs (1) and (2) 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 systems spray area, a dry litter poultry facility and fifty (50) feet from any property line provided the well is located at the minimum horizontal distance from the sources of potential contamination.
   5. (5) 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.

   6. (6) The following are exceptions to the property line distance requirement where:

      1. (A) groundwater conservation district rules are in place regulating the spacing of wells;
      2. (B) platted or deed restricted subdivision regulated spacing of wells and on-site sewage systems are part of planning; or
      3. (C) public wastewater treatment is provided and utilized by the landowner.

2. (b) In all wells where plastic casing is used, except when a steel or polyvinyl chloride (PVC) sleeve or pitless adapter, as described in subsection (c) is used, a concrete slab or sealing block shall be placed above the cement slurry around the well at the ground surface.

   1. (1) 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.
   2. (2) The surface of the slab shall be sloped to drain away from the well.
   3. (3) 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 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 so as 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.
   4. (4) 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; after 48 hours, the well must be completed in accordance with this section or plugged in accordance with §76.104.
   5. (5) 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 meets the standards pursuant to Texas Commission on Environmental Quality 30 TAC Chapter 331.

3. (c) In wells where a steel or PVC sleeve is used:

   1. (1) The steel sleeve shall be a minimum of 3/16 inches in thickness and/or the plastic sleeve shall be a minimum of Schedule 80 sun resistant or SDR 17 in the 6" and 8" inch sun resistant and be twenty four (24) inches in length, and 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 a minimum of twelve (12) inches above the land surface, and the steel/plastic sleeve shall be two (2) inches larger in diameter than the plastic casing being used and filled entirely with cement; or

   2. (2) A slab or block as described in this subsection 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:

      1. (A) the adapter is welded to the casing or fitted with another suitably effective seal;
      2. (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
      3. (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.
4. (d) All wells shall be completed so that aquifers or zones containing waters that differ in chemical quality are not allowed to commingle through the borehole-casing annulus or the gravel pack and cause quality degradation of any aquifer or zone.
5. (e) The well casing shall be capped or completed in a manner that will prevent pollutants from entering the well.
6. (f) Each licensee shall use potable water in drilling fluids.
7. (g) 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 owners' written consent.
8. (h) 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.
9. (i) Unless waived by written request from the landowner, a new, repaired, or reconditioned well or pump installation or repair on a well used to supply water for human consumption shall be properly disinfected. The well shall be properly disinfected with chlorine or other appropriate disinfecting agent under the circumstances. A disinfecting solution with a minimum concentration of fifty (50) milligrams per liter (mg/l) (same as parts per million), shall be placed in the well as required by the American Water Works Association (AWWA), pursuant to ANST/AWWA C654-87 and the United States Environmental Protection Agency (EPA).

10. (j) A licensed installer shall disinfect the well by:

    1. (1) treating the water in the well casing to provide an average disinfectant residual to the entire volume of water in the well casing of fifty (50) mg/l. This may be accomplished by the addition of calcium hypochlorite tablets or sodium hypochlorite solution in the prescribed amounts;
    2. (2) circulating, to the extent possible, the disinfected water in the well casing and pump column; and
    3. (3) pumping the well to remove disinfected water for a minimum of fifteen (15) minutes.
    4. (4) If calcium hypochlorite (granules or tablets) is used, it is suggested that the installer dribble the tablets of approximately five-gram (g) size down the casing vent and wait at least thirty (30) minutes for the tablets to fall through the water and dissolve. If sodium hypochlorite (liquid solution) is used, care should be taken that the solution reaches all parts of the well. It is suggested that a tube be used to pipe the solution through the well-casing vent so that it reaches the bottom of the well. The tube may then be withdrawn as the sodium hypochlorite solution is pumped through the tube. After the disinfectant has been applied, the installer should surge the well at least three times to improve the mixing and to induce contact of disinfected water with the adjacent aquifer. The installer should then allow the disinfected water to rest in the casing for at least twelve hours, but for not more than twenty-four hours. Where possible, the installer should pump the well for a minimum of fifteen (15) minutes after completing the disinfection procedures set forth above until a zero disinfectant residual is obtained. In wells where bacteriological contamination is suspected, the installer shall inform the well or property owner that bacteriological testing may be necessary or desirable.
11. (k) A test well that is drilled for exploring for groundwater shall not be open at the surface or allowing water zones of different chemical quality to commingle and must be completed or plugged within six (6) months of drilling.
12. (l) Water wells located within public water supply system sanitary easements must be constructed to public well standards pursuant to 30 TAC Chapter 290.
13. (m) Pump column material that has been used in the production of oil or gas or has been exposed to contamination may not be placed in a well regulated by this department.

Source Note:The provisions of this §76.100 adopted to be effective March 1, 2013, 38 TexReg 1142.