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Ground Water Rule

The Ground Water Rule (GWR) protects your drinking water quality and provides additional protection from disease-causing microorganisms.

Water systems that have groundwater sources may be susceptible to fecal contamination which can contain disease causing pathogens. The GWR provides increased public health protection against microbial pathogens.

The GWR applies to all public water systems that provide groundwater, except public water systems that combine all of their groundwater with surface water prior to treatment.

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What is the purpose of this rule?

This rule protects Texas' drinking water by requiring action to protect groundwater sources of public drinking water suppliers from disease-causing viruses and bacteria, such as E. coli. The rule protects more than 10 million Texans by requiring identification of deficiencies in water systems that could lead to contamination and corrective actions to reduce risk from any identified deficiencies. The rule includes provisions for monitoring for systems with sources at risk, and actions to remove or inactivate contaminants, if found, to prevent them from reaching drinking water consumers.

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What types of pathogens can be found in water provided by groundwater systems?

Groundwater that is susceptible to fecal contamination may contain harmful viruses or bacteria. Viral pathogens found in GWSs may include enteric viruses such as Echovirus, Hepatitis A and E, Rotavirus and Noroviruses (i.e., Norwalk-like viruses) and enteric bacterial pathogens such as Escherichia coli (including E. coli O157:H7), Salmonella species, Shigella species, and Vibrio cholerae.

Ingestion of these pathogens can cause gastroenteritis or, in certain rare cases, serious illnesses such as meningitis, hepatitis, or myocarditis. Health implications in sensitive subpopulations may be severe (e.g., hemolytic uremic syndrome) and may cause death.

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What causes contamination of groundwater?

Viral and bacterial pathogens are present in human and animal feces, which can, in turn, contaminate drinking water. Fecal contamination can reach groundwater sources, including drinking water wells, from failed septic systems, leaking sewer lines, and by passing through the soil and large cracks in the ground. Fecal contamination from the surface may also get into a drinking water well along its casing or through cracks if the well is not properly constructed, protected, or maintained.

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Does this rule address private water wells? If not, how does EPA help protect them?

This rule does not address private wells because they are not under the jurisdiction of the Safe Drinking Water Act and are therefore not subject to TCEQ regulation. TCEQ recommends that well owners periodically test their water for microbial and chemical contaminants and properly maintain their well. Information is available on EPA's Private Wells Web site.Exit the TCEQ

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What are the basic requirements of the rule?

The risk-targeting strategy incorporated into the rule provides for:

  • regular sanitary surveys of public water systems to look for significant deficiencies in key operational areas;
  • triggered source water monitoring when a system identifies a positive sample during its Revised Total Coliform Rule monitoring and assessment monitoring targeted at high-risk systems;
  • implementation of corrective actions by groundwater systems with a significant deficiency or evidence of source water fecal contamination to reduce the risk of contamination; and,
  • compliance monitoring for systems that are sufficiently disinfecting drinking water to ensure that the treatment is effective at removing pathogens.

EPA's Ground Water Rule pageExit the TCEQ 

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What is a sanitary survey?

A sanitary survey is review conducted by the state that looks at critical components of a public water system. At TCEQ, the Regional staff perform Comprehensive Compliance Investigations to meet the EPA's sanitary survey requirement. The sanitary survey provisions in this rule build on existing state programs such as the Revised Total Coliform Rule and the Interim Enhanced Surface Water Treatment Rule and give states the authority to define eight specific components that must be reviewed during a survey (to the extent that they apply to the individual water system being surveyed):

  1. source:
  2. treatment;
  3. distribution system;
  4. finished water storage;
  5. pumps, pump facilities, and controls;
  6. monitoring, reporting, and data verification;
  7. system management and operation; and
  8. operator compliance with state requirements.

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What is a significant deficiency?

Significant deficiencies cause, or have the potential to cause, the introduction of contamination into water delivered to customers. This could include defects in design, operation, or maintenance of the source, treatment or distribution systems. They could also be represented by the failure or malfunction of those systems.

Some of the following significant deficiencies are addressed during Comprehensive Compliance Investigations. The TCEQ ultimately determines whether or not a deficiency is considered "significant". Please note that this list does not represent all possible significant deficiencies.

  1. Source:
    • No well site shall be located within 50 feet of a tile or concrete sanitary sewer, sewerage appurtenance, septic tank, storm sewer, or cemetery; or within 150 feet of a septic tank perforated drainfield.
  2. Treatment:
    • All groundwater must be disinfected prior to distribution. The point of the application must be ahead of the water storage tank.
    • Disinfection equipment shall have a capacity of at least 50% greater than the highest expected dosage to be applied at any time.
    • Exposure of the water to the atmosphere shall provide for subsequent disinfection ahead of storage tanks, shall prevent foreign materials from getting into the water, and aerators shall be screened.
  3. Distribution System:
    • Accurate testing equipment must be used by the water system.
    • Disinfection equipment shall maintain:
      • free chlorine residual of 0.2 mg/L: OR
      • chloramines residual of 0.5 mg/L
  4. Finished Water Storage
    • No public water system storage tank shall be located within 500 feet of any municipal or industrial sewage treatment plant or any land which is spray irrigated with treated sewage effluent or sludge disposal.
  5. Pumps, Pump Facilities, and Controls:
    • Upon well completion, or after a well has been reworked, the well shall be disinfected in accordance with current American Water Works Association standards, except that the disinfection shall remain in the well for at least six hours.
    • Service connections that require booster pumps taking suction from the public water system must be equipped with automatic pressure cut-off devices ensuring pumping units are inoperative at less than 20 psi.
  6. Monitoring, Reporting, and Data Verification:
    • The following records shall be retained for at least five years:
    • Microbiological analyses.
    • Invalidated fecal indicator samples.
  7. System Management and Operation:
    • Emergency power, elevated storage, or interconnect with another system required for systems which serve more than 250 connections.
  8. Operator Compliance:
    • Groundwater systems shall meet the following requirements:
      • No more than 250 connections - Must employ an operator with a Class D or higher license.
      • Between 250 and 1000 connections - Must employ an operator with a Class C or higher groundwater license.
      • More than 1000 connections - Must employ two or more Class C or higher groundwater licensed operators and they must work 16 hours per month at the public water system.

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What are the monitoring provisions?

If a system receives notice of a total Coliform-positive distribution system sample collected under the Revised Total Coliform Rule (RTCR), it must take a source water sample within 24 hours. The system does not have to take the sample if the state can determine that the positive sample was due to an issue in the distribution system and not the source. TCEQ may require immediate corrective action to address contamination at those sites.

For those systems that already treat drinking water to at least 99.99 percent (4-log) inactivation or removal of viruses, the rule requires regular compliance monitoring to ensure that the treatment technology installed is reliably inactivating and removing contaminants.

There are basically three monitoring options for systems to use under the GWR:

    1. Systems can claim 4-Log treatment by providing a Concentration-Time (CT) Study for approval by the TCEQ and then maintain 4-Log treatment through daily or continuous residual monitoring (depending on population) and documenting this using the Groundwater Monthly Operating Report form.
    2. Systems can perform representative triggered source monitoring outlined in a TCEQ approved triggered source monitoring plan (TSMP).  The TSMP can reduce the required triggered source samples by identifying representative sources.

Send triggered source monitoring plans to:

Triggered Source Monitoring Plans
Drinking Water Assessment Team MC - 155
P.O. Box 13087
Austin, TX 78711-3087"
Phone: 512/239-4691
Fax: 512/239-6050

  • Systems can perform triggered source monitoring by collecting samples from every active well in the event of a distribution system total coliform positive routine Revised Total Coliform Rule (RTCR) sample if options 1 or 2 are not used. This option is good for systems that do not have many wells, do not perform 4-Log treatment, and do not have a history of having many positives in the distribution system.

Options 1 and 2 require TCEQ approval. Under option 3, systems do not have any required action until a coliform positive is collected in the distribution system.

The GWR also gives states the option to require systems that do not provide sufficient disinfection treatment that achieves 99.99 percent inactivation of viruses to conduct assessment source water monitoring at any time. The TCEQ may evaluate the need for assessment source water monitoring on a case by case basis. The following risk factors will be considered in targeting high-risk systems:

  • wells in karst, fractured bedrock, gravel, or other sensitive aquifers;
  • wells in shallow unconfined aquifers
  • wells in aquifers with thin or no soil cover;
  • presence of potential sources of fecal contamination;
  • depth and location of the groundwater source; and
  • wells previously identified as having been fecally contaminated.

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What are the corrective actions a groundwater system must implement?

When a system has a significant deficiency or a fecal indicator-positive groundwater source sample (either by the initial triggered sample, or positive repeat sample, as determined by the state), the TCEQ requires the groundwater system to implement one or more of the following corrective action options:

  • correct all significant deficiencies (e.g., repairs to well pads and sanitary seals, repairs to piping tanks and treatment equipment, control of cross-connections);
  • provide an alternate source of water (e.g., new well, connection to another PWS);
  • eliminate the source of contamination (e.g., remove point sources, relocate pipelines and waste disposal, redirect drainage or run-off, provide or fix existing fencing or housing of the wellhead); or
  • provide treatment that reliably achieves at least 4-log treatment of viruses (using inactivation, removal, or a state-approved combination of 4-log virus inactivation and removal).
  • well disinfection in accordance with American Water Works Association procedures link to AWWA C654-03, Disinfection of WellsExit the TCEQ
  • a state-specified period of source monitoring

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Where can I access documents related to the Ground Water Rule?

The following links are to other forms associated with the Ground Water Rule:

Presentations from an American Water Works Association Ground Water Rule Webcast:

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Contact the Public Drinking Water Section