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Dental Offices: Wastewater Discharge Rule

Requirements for discharging wastewater from dental offices including those that place or remove dental amalgam. Who is regulated and who is exempt, rules, reporting, and best management practices to implement.

Effective July 14, 2017, the U.S. Environmental Protection Agency (EPA) adopted the Effluent Limitations Guidelines and Standards for the Dental Category Final Rule to reduce the discharge of mercury-containing amalgam from dental offices into publicly owned treatment works (POTWs). 40 Code of Federal Regulations (CFR) Part 441

The effective date for these requirements is July 19, 2018. (Adopted June 27, 2018 by reference in Title 30, Texas Administrative Code (30 TAC), Section 305.541 )

Is my wastewater treatment plant a POTW?

  • Yes, if owned by a municipality or a political subdivision such as a municipal utility district (MUD)
  • No, if owned by an individual, corporation or cooperative corporation such as a sewer or water supply corporation

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Am I regulated by this rule?

If your office places or removes amalgam and discharges wastewater to a POTW you must comply with the rule.

If your office does not place or remove dental amalgam, except in limited emergency or unplanned, unanticipated circumstances, you must submit a one-time compliance report to your pretreatment Control Authority but are exempt from any further requirements. (See Who is my Control Authority and Where should I send my report? below).

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Am I exempt?

The following dental offices are not subject to these requirements:

  • an office that exclusively practices one or more of the following: oral pathology, oral and maxillofacial radiology, oral and maxillofacial surgery, orthodontics, periodontics, or prosthodontics
  • a mobile unit, which consists of a specialized, self-contained van, trailer, or equipment used in providing dentistry services at multiple locations
  • an office that does not discharge amalgam process wastewater into a POTW

Note: TCEQ does not allow the discharge of any industrial wastewater to an on-site septic system (OSSF).

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What do I need to do if the rule applies to my office?

  • Install, operate, maintain, and inspect amalgam separators and removal devices.
  • Implement these best management practices if you discharge to a POTW:
    1. Do not discharge waste amalgam including, but not limited to, dental amalgam from chair-side traps, screens, vacuum pump filters, dental tools, cuspidors, or collection devices.
    2. When cleaning dental unit water lines, chair-side traps, and vacuum lines that discharge amalgam process wastewater, do not use oxidizing or acidic cleaners, including but not limited to bleach, chlorine, iodine and peroxide that have a pH lower than 6 or greater than 8.
  • Submit a report to your Control Authority.

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Who is my Control Authority (CA)?

  • This may be your local POTW or the TCEQ.
  • Look for your dental office’s city on this Texas CA ListAdobe Acrobat PDF Document.
  • If you find your CA, contact them to determine if they have a specific form or if you can submit information electronically.
  • If your city was not on the list, the TCEQ is your Control Authority.

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Where should I send my report?

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When is my deadline?

If your office opened on or before July 14, 2017:

  • comply with the rule by July 14, 2020
  • submit your report by October 12, 2020

If ownership is transferred after July 15, 2020, the new owner has 90 days after the transfer date to send the report to their Control Authority.

If your office opened after July 14, 2017:

  • implement the rule requirements immediately
  • submit the report within 90 days after the first discharge of wastewater

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Where can I find more information?

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Who can I contact for help?

Small Business and Local Government Assistance: (free, confidential help)

  • 1-800-447-2827

Pretreatment Program Assistance:

  • 512-239-4671

Mailing Address:
Water Quality Division MC-148
Texas Commission on Environmental Quality
P.O. Box 13087
Austin, Texas 78711-3087

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