Dental Amalgam Rule

Dental Amalgam Guidelines

The United States Environmental Protection Agency (EPA) has introduced pretreatment standards to reduce discharges of mercury from dental offices into publicly owned treatment works (POTWs). The Dental Office Category regulation is codified at 40 CFR Part 441.

Dental offices discharge mercury present in amalgam used for fillings. Amalgam separators are a practical, affordable and readily available technology for capturing mercury and other metals before they are discharged to POTWs. Once captured by a separator, mercury can be recycled.

EPA expects compliance with this final rule will annually reduce the discharge of mercury by 5.1 tons as well as 5.3 tons of other metals found in waste dental amalgam to POTWs.

Key facts about dental clinics and mercury:

  • Dental clinics are the main source of mercury discharges to POTWs.
  • EPA estimates about 103,000 dental offices use or remove amalgam in the United States; almost all of these send their wastewater to POTWs.
  • Dentists discharge approximately 5.1 tons of mercury each year to POTWs; most of this mercury is subsequently released to the environment.

Mercury-containing amalgam wastes may find their way into the environment when new fillings are placed or old mercury-containing fillings are drilled out and waste amalgam materials are flushed into chair-side drains and then enter the POTW. Mercury entering POTWs typically ends up in the biosolids, the solid material that remains after wastewater is treated. Mercury from waste amalgam therefore can make its way into the environment from the POTW through the land application of biosolids or through surface water discharge.

Various informative links and downloads from the EPA and the American Dental Association are available below.

Reporting Requirements

Dental offices that place or remove amalgam must operate and maintain an amalgam separator and must not discharge scrap amalgam or use certain kinds of line cleaners. Existing and new sources must submit a One-Time Compliance Report for Dental Dischargers (PDF) to the City of St. Joseph's Water Protection Division.

This form can be filled out electronically, printed and signed, and mailed to the addresses included on the form.


One-Time Compliance Report for Dental Dischargers (PDF)

Frequently Asked Questions on The Dental Office Category Rule (PDF)

ADA Best Management Practices for Amalgam Waste (PDF)


Federal Regulation – 40 CFR Part 441 – Dental Office Point Source Category

ADA Amalgam Separators and Waste Best Management Practices