Dental Office Point Source Category


The Environmental Protection Agency (EPA) is implementing technology-based pretreatment standards under the Clean Water Act to reduce discharges of mercury from dental offices into municipal sewage treatment plants known as publicly owned treatment works (POTWs).  The new Dental Office Point Source Category requires dental offices to utilize amalgam separators and implement two Best Management Practices (BMPs) as recommended by the American Dental Association.

The Dental Office Point Source Category becomes effective on July 14, 2017.

  •  Existing Dental Offices must comply with the new standards within 3 years.

  •  New Dental Offices must comply immediately.  

OCSD is in the process of developing a compliance program for the applicable dental offices in the Orange County Sanitation District’s (OCSD) service area so they can comply with this rule.


In order to simplify implementation and compliance with the rule for the dental offices, as well as the regulating Control Authority, the rule establishes that dental dischargers are not Significant Industrial Users (SIUs) nor Categorical Industrial Users (CIUs) subject to categorical pretreatment standards.  While the rule establishes pretreatment standards that require the dental offices to reduce dental amalgam discharges, the rule does not require the Control Authority to implement the traditional oversight requirements in the General Pretreatment Regulations.  This significantly reduces the reporting requirements for dental dischargers that would otherwise apply. All dental offices within OCSD’s service area will eventually need to submit a Compliance Report.  The amount of information that must be supplied on the report form depends on the level of amalgam procedures conducted by the dental practice.  If the practice expects to remove or place amalgam at a frequency of more than 5 percent of the procedures, then slightly more information including the details of the amalgam separator are required.


OCSD will add links to Frequently Asked Questions and the Compliance Report form to this website after obtaining guidance from the EPA regarding expectations for the new category.  Please see the EPA website for links to the detailed Dental Category development document, effluent guidelines, and fact sheet

The Dental Office Point Source Category regulation is codified at 40 CFR Part 441 .

For more information on OCSD’s Dental Amalgam Program, please contact:

Merrill Seiler, Principal Environmental Specialist
714-593-7436  or