Requirements for Wells

A well that is not in compliance may need an exception to one or more TCEQ regulations.

A proposed well, or an existing well with significant changes, may need plans and specifications for the well to be submitted and reviewed by the TCEQ.

Required Bacteriological Samples When a PWS Well Pump is Repaired or Replaced

30 TAC 290.41(c)(3)(F) requires that before a well is placed in service after completion or an existing well has been reworked, the well must be disinfected and the water containing the disinfectant must be flushed from the well. The reworking of a well is interpreted as the deepening, cleaning and jetting, or other major construction or renovation. Once a well has been reworked and flushing has occurred, bacteriological samples (labeled as a “special” sample), must then be collected and submitted for microbiological analysis until three successive daily raw water samples are free of coliform organisms.

One raw water bacteriological sample (labeled as a “special” sample) must be collected for minor well repairs or when a well pump has been repaired or replaced and the well has not been reworked. All traces of chlorine must be flushed from the well before the sample is collected. A TCEQ accredited laboratory must certify that the sample is free of coliform organisms before the well can be returned to service. The pulling of a pump for replacement or repair is not the same type of activity as reworking, and a single bacteriological sample is considered adequate.

Polyvinyl Chloride (PVC) Casing for Proposed PWS Wells

30 TAC 290.41(c)(3)(B) and 30 TAC 290.41(c)(l)(A) requires the well casing for proposed PWS wells shall have sufficient mechanical strength to withstand the forces expected during installation, cementation and normal service. These forces increase with increased well depth. The selection of the well casing material should allow for the expected increase. Accordingly, the minimum wall thicknesses for PVC well casing shall take into account the following:

• The PVC well casing shall conform to American Society for Testing and Materials (ASTM) F480 and must be designed based on a potential for hydraulic collapse considering external and internal pressures.
• In all cases, the PVC casing pipe shall be labeled “NSF-pw" by the pipe manufacturer, conform to American National Standards Institute/National Sanitation Foundation Standard (ANSI/NSF) Standard 14 and must be certified by an organization accredited by ANSI.
• PVC casing shall not be approved for use in the construction of a PWS well under any of the following circumstances:

1. An exception has been requested and/or granted to the required separation distances specified in 30 TAC 290.41(c)(l)(A) to allow the construction of the proposed PWS well within 150 feet of an underground petroleum and chemical storage tank or liquid transmission pipeline.
2. The proposed PWS well location is within the boundaries of a Volatile Organic Compound plume or contaminated soil.
3. The capture zone of the proposed PWS well will intersect groundwater containing VOCs in sufficient quantity to dissolve or degrade the PVC well casing.

Pressure Cementing of PWS Wells

30 TAC 290.41(c)(3)(C) requires PWS wells, the space between the casing and the drill hole shall be sealed by cement under pressure, and that the well casing shall be pressure cemented from the top of the shallowest formation to be developed to the earth's surface.

In sealing the annular space, the driller must use cement in accordance with American Water Works Association (AWWA) Standard for Water Wells (A100-06 or latest standard) Section 4.3.5.1 which states that neat cement shall consist of a mixture of American Petroleum Institute Spec. 10, Class A (similar to ASTM C150, type 1) or Class B (similar to ASTM C 150, type 2) and water in the ratio of not more than 6.0 gallons of water per 94 pound sack of cement weighing approximately 118 lb/ft3. A maximum of 6 percent, by weight, bentonite and 2 percent, by weight, calcium chloride may be added.

The annular space to be cemented is the space between the outside diameter of the inner well casing and the inside diameter of the outer well casing or borehole. (EPA-570/9-75-001)

Some engineers and water well drillers have assumed that the Tremie Method (as specified in AWWA Standards for Water Wells, A100-06, Appendix C, Section C.1) is an acceptable method of pressure cementation. Engineers and drillers confuse the Tremie Method with the Positive Displacement-Exterior Method (AWWA Standards for Water Wells, A100-06, Appendix C, Section C.2) which can also use a tremie tube. The difference between the two methods is that the Positive Displacement-Exterior Method requires the grout material to be placed by pumping or forced injection by air pressure. In contrast, the Tremie Method involves pouring the grout material into a tremie tube. Pouring of grout material is not regarded as pressure cementation.

Engineers and water well drillers have also misinterpreted the meaning of the language "shallowest formation to be developed". This language means the shallowest saturated deposit from which drinking water will be produced in the public water supply well. This regulatory language does not refer to the shallowest stratigraphic formation to be developed or to the shallowest ground water encountered by the well. Determination of the depth of required cementation must consider water-level fluctuations in unconfined or partially confined aquifers, and protection of the well from undesirable water or potential sources of contamination.

The following guidance provides acceptable methods and depth requirements for the pressure cementation of public water supply wells:

1. The driller will utilize the following pressure cementation methods in accordance with the AWWA Standard for Water Wells (A100-06 or latest standard), Appendix C: Section C.2 (positive displacement-exterior method); Section C.3 (interior method-without a plug); Section C.4 (positive placement-interior method-drillable plug); or Section C.5 (placement through float shoe attached to the bottom of the casing).
2. Tremie Method (A100-06 Section C.1) is not a pressure cementation method and does not meet the requirements of 30 TAC §290.41(c)(3)(C). Use of a tremie tube with a pump is allowed with the Positive Displacement-Exterior Method (A100-06, Section C.2).
3. Exceptions to the requirement that a well be pressure cemented down to the producing aquifer (shallowest formation to be developed) will not be granted without a detailed evaluation by commission staff.

Restriction on the Use of Bentonite in PWS Wells

A risk of water source contamination is associated with improper use of bentonite mixtures in unsaturated or semisaturated zones where the moisture content of the mixture fluctuates. Under such conditions, the bentonite mixture may crack, or otherwise degrade, and not provide an adequate barrier to contaminants. Therefore, bentonite may be used only in the following application:

• A bentonite plug may be used in a water saturated zone to seal the annular space above the packer. The plug may not exceed ten feet in height and the entire plug shall be below the water table at all times. The placement of the plug and the grout seal shall be a continuous operation to minimize the possibility of voids in the seal.

Water Saturated Zone – a water saturated zone is a layer below the water table where the interstices are completely filled with water at all times.

Licensed Professional Engineer (P.E.) and Licensed Well Driller Requirements for PWS Well Rehabilitation or Repair

Generally, the replacement of well-related items with the same components having the same material type, size and capacity does not require a P.E., but will require a licensed well driller. Repair or replacement of a well pump will require a licensed pump installer. New components or modifications fall under 30 TAC 290.39(j) and will require written notification to the TCEQ. An engineer's involvement may not be required. See the charts below for clarification:

Below-Ground Maintenance

Above-Ground Maintenance

Resources

• TCEQ Drinking Water Watch
• TCEQ Forms and Checklists for Submitting Plans or Specifications for PWS
• TCEQ Requesting an Exception to Rules and Regulations for PWS
• TDLR Drilling reports
• TWDB Groundwater Conservation District
  • If your well is located within an underground water district, the district might have a copy of the well log. Our Groundwater Planning and Assessment Team coordinates the TCEQ programs for groundwater conservation districts
• TWDB Groundwater Database
  • If you find the well and click on it, a blue link in the description that pops up opens a window. Click on scan. Sometimes you find the well report and chemical testing.
• TCEQ Central Records Search.
  • A searchable index of all records housed in our central file room can be viewed  and may contain the 1960’s health survey that has the well information.
• NSF
  • Search Certified PWS Chemicals
  • Search Certified PWS Components
• Pump Curves – Conduct an internet search of the maker of pump and pump model from pump tag.
• TCEQ’s Water Well Report Viewer
  • Map-based locator of over 800,000 historical reports for water wells drilled in Texas.
• AWWA Publications
• TCEQ Groundwater Contamination Viewer

Contacts

If you have questions or need to discuss some specific issue in complying with its requirements as they apply to your PWS, you may call 512-239-4691 and ask to speak to a member of the Technical Review and Oversight Team or the Plan Review Team. You can also try the TCEQ Exceptions webpage for further exceptions information or the TCEQ Plan Review webpage.