Dental Office Pretreatment Standards

The Environmental Protection Agency (EPA) has promulgated technology-based Pretreatment Standards under the Clean Water Act to reduce discharges of mercury from dental offices into publicly owned treatment works (POTWs), i.e., municipal sewer systems. In the practice of dentistry, amalgam is typically used to fill cavities caused by tooth decay. Amalgam is a metal alloy that contains up to 50% mercury in its composition. The federal regulations at 40 CFR §441 require dental offices to use amalgam separators and two best management practices (BMPs) recommended by the American Dental Association (ADA).


Dental offices subject to these Pretreatment Standards are referred to as dental dischargers. A dental discharger, as defined at 40 CFR §441.20(e), is a facility where the practice of dentistry is performed, including, but not limited to, institutions, permanent or temporary offices, clinics, home offices, and facilities owned and operated by Federal, state or local governments, that discharges wastewater to a POTW. The following types of dental dischargers are excluded from the requirements of §441:

  • Dental dischargers that exclusively practice one or more of the following dental specialties:
    • - oral pathology
    • - oral and maxillofacial radiology
    • - oral and maxillofacial surgery
    • - orthodontics
    • - periodontics
    • - prosthodontics
  • Dental dischargers operating a mobile unit, defined at 40 CFR §441.20(h) as a specialized mobile self-contained van, trailer, or equipment used in providing dentistry services at multiple locations.
  • Dental dischargers that do not discharge any amalgam process wastewater to a POTW.
  • Dental dischargers that do not place dental amalgam, and do not remove amalgam except in limited emergency or unplanned, unanticipated circumstances, and that certify such as required in 40 CFR §441.50.

For more information on how to determine applicability status, please contact the Office of Water Quality:

Office of Water Quality Pretreatment Contact


Subject dental dischargers must achieve the following Pretreatment Standards:

  • Installation, operation, and maintenance of one or more amalgam separators that meet the requirements of 40 CFR §441.30(a)(1) or an equivalent amalgam removal device(s) that meets the requirements of 40 CFR §441.30(a)(2).
  • Implementation of the following BMPs:
    • - Waste amalgam including, but not limited to, dental amalgam from chair-side traps, screens, vacuum pump filters, dental tools, cuspidors, or collection devices, must not be discharged to a POTW.
    • - Dental unit water lines, chair-side traps, and vacuum lines that discharge amalgam process wastewater to a POTW must not be cleaned with 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.

Upon achieving compliance with the above Pretreatment Standards, dental dischargers must submit the following report:

One-Time Compliance Report

Where to submit the One-Time Compliance Report?

Subject dental dischargers located in any of the following municipalities, should contact the respective point of contact for submittal details:

Pretreatment Cities

All other subject dental dischargers may submit the One-Time Compliance Report to the Office of Water Quality, Division of Environmental Quality via any of the following methods:

Email [with document(s) attached in PDF format]:


Division of Environmental Quality
Office of Water Quality
5301 Northshore Drive
North Little Rock, AR 72118-5317

Additional Information