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 became effective on July 14, 2017.

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

  •  New Dental Offices must comply immediately.  

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


To simplify implementation and compliance for the dental offices, the rule establishes that dental dischargers are not Significant Industrial Users (SIUs) nor Categorical Industrial Users (CIUs) subject to categorical Pretreatment Standards.  This significantly reduces the reporting requirements that would otherwise apply. However, most dental offices within OCSD’s service area will eventually need to submit a Compliance Report to OCSD as the regulatory Control Authority.

Who is affected?  The rule applies to wastewater discharges to POTWs from offices where the practice of dentistry is performed, including large institutions such as dental schools and clinics; permanent or temporary offices; home offices; and dental offices owned and operated by federal, state, or local governments including military bases.

Are there exemptions?  Yes, the rule does not apply to dental dischargers that exclusively practice one or more of the following dental specialties Oral Pathology; Oral & Maxillofacial Radiology; Oral and Maxillofacial Surgery; Orthodontics; Periodontics; or, Prosthodontics, and it does not apply to Dental Mobile Units.

Dental Dischargers that do not place dental amalgam, and do not remove dental amalgam except in limited emergency or unplanned, unanticipated circumstances are exempt from any further requirements of the rule as long as they certify such in the Compliance Report to OCSD.


OCSD is planning to add Frequently Asked Questions and links to the Compliance Report forms to this website in the near future.  In the interim, 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

Page Revised: July 26, 2017