United States
Environmental Protection
\*^l m %Agency
Office of Water
EPA 822-S-17-002
November 2017
Frequently Asked Questions on the
Dental Office Category Rule
EPA developed these FAQs based on the Dental Office Category Rule at 40 CFR Part 441. Dental facilities may
be subject to additional or more stringent state or local requirements than those in the rule.
Who must comply with this rule?
The vast majority of dental facilities that discharge wastewater into a publicly owned treatment works (POTW)
(e.g., municipal sewage system) are subject to this rule ("dental dischargers"). However, there are some
exceptions.
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 as long as
they certify as such in a one-time compliance report to their Control Authority.
Dental dischargers that exclusively practice one or more of the following specialties are not subject to any of
the rule's requirements, including submission of a one-time compliance report to their Control Authority:
	Oral pathology
	Oral and maxillofacial radiology
	Oral and maxillofacial surgery
	Orthodontics
	Periodontics
	Prosthodontics
Additionally, mobile units are not subject to any of the rule's requirements, including submission of a one-time
compliance report to their Control Authority. A mobile unit is a specialized mobile self-contained van, trailer,
or equipment used in providing dentistry services at multiple locations.
Dental facilities that do not discharge their amalgam process wastewater into a POTW are also not subject to
any of the rule's requirements, including submission of a one-time compliance report to their Control
Authority. For example, dental facilities that discharge amalgam process wastewater into a septic system are
not subject to this rule.
To determine if the EPA rule applies to your facility, see  441.10 (Applicability).

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What are the basic requirements of the rule?
The requirements for dental dischargers subject to the rule are detailed in the rule. Here, they are summarized
as follows:
	Ensure the removal of dental amalgam solids from all amalgam process wastewater via amalgam
separator(s) or equivalent device(s) that meet the standard of the final rule. See  441.30(a)(l-2) for an
existing source and  441.40 for a new source.
	Implementation of two best management practices. See  441.30(b) for an existing source and
 441.40 for a new source.
	Comply with reporting requirements. See  441.50(a).
	Maintain and make available for inspection certain records documenting compliance. See  441.50(b).
What are the compliance deadlines?
Dental dischargers (under any ownership) that were discharging into POTWs prior to July 14, 2017 ("existing
sources"), must be in compliance with the standards by July 14, 2020, and submit a one-time compliance
report certifying such by October 12, 2020.
Dental dischargers whose first discharge to a POTW occurs after July 14, 2017 ("new sources") must be in
compliance with the standards immediately and submit a one-time compliance report certifying such within
90 days after first discharge to a POTW.
If the dental discharger transfers ownership, what are the deadlines for a new owner to submit a one-time
compliance report?
If an "existing source" dental discharger transfers ownership, the new owner must submit a new one-time
compliance report to the Control Authority by October 12, 2020, or if the transfer occurs after July 15, 2020,
no later than 90 days after the transfer. If a "new source" dental discharger transfers ownership, the new
owner must submit a new one-time compliance report to the Control Authority no later than 90 days after the
transfer.
Does this rule require standards for the type of amalgam separator I install?
Yes. For an existing source see  441.30(a)(l-2). For a new source, see  441.40.
Do I have to replace my existing separator?
It depends.  441.30(a)(l)(iii) of the rule allows dental dischargers that had installed and were using an
amalgam separator prior to June 14, 2017 to continue to use it until June 14, 2027 if it is functioning properly
and does not need to be replaced. This is referred to as a "grandfathering" provision or clause. The facility
must still file a one-time compliance report certifying such by October 12, 2020. If the amalgam separator
meets the standards of the rule, see  441.30(a)(l-2). the grandfathering provision need not apply.
If a dental discharger covered by the grandfather clause transfers ownership, the new owner may continue
using the grandfathered separator until June 14, 2027 if it is functioning properly and does not need to be
replaced. The new owner must still file the one-time compliance report.
What are the correct dates that are relevant to the grandfathering provision in  441.30(a)(l)(iii)?
In the original Federal Register publication of the final rule, there was a typographical error in one of the dates
in the grandfathering provision. The corrected version of the provision is: "A dental discharger subject to this
part that operates an amalgam separator that was installed at a dental facility prior to June 14, 2017, satisfies
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the requirements of paragraphs (a)(l)(i) and (ii) of this section until the existing separator is replaced as
described in paragraph (a)(l)(v) of this section or until June 14, 2027, whichever is sooner." (emphasis added)
I have a wastewater retaining tank technology that collects all amalgam process wastewater and my dental
facility does not discharge any amalgam process wastewater to a POTW. Am I exempt from the Dental
Office Category Rule?
Yes. See  441.10(e). As long as the dental facility does not discharge any amalgam process wastewater from
the tank or otherwise, it is not subject to any of the rule's requirements, including submission of a one-time
compliance report to their Control Authority.
My dental facility has a technology that removes amalgam from wastewater as efficiently as an amalgam
separator, but it is a different type of device, and therefore does not qualify to meet the ISO standard for
amalgam separators. Does this device satisfy the requirements of this rule?
The rule includes a provision at  441.30(a)(2) that allows the performance standard of the rule to be met with
the use of an amalgam-removing technology other than an amalgam separator (i.e., equivalent device). EPA
included this provision to allow use of amalgam removal devices that are equivalent to amalgam separators in
several respects (e.g. the percentage of removal of mass of solids) but that may not fall under the amalgam
separator classification. The equivalent device is required to meet the same requirements and removal
efficiencies, as specified in  441.30(a)(l-2) or  441.40.
Does this rule have recordkeeping requirements for dental dischargers?
Yes. See 441.50.
Does this rule have inspection or maintenance requirements for dental dischargers?
Yes. See 441.30.
What information must be in my one-time compliance report?
See  441.50. A sample one-time compliance report that includes the information required by the rule may be
found at www.epa.gov/eg/dental-effluent-guidelines.
	Note to dental dischargers: Please contact your Control Authority to ensure that you have obtained the
correct form from your Control Authority. In addition, you may be subject to additional reporting
requirements in accordance with state and local law.
Where should dental dischargers send their one-time compliance report? Who is my "Control Authority?"
Dentists should obtain and send their one-time compliance report to their pretreatment Control Authority.
Your Control Authority is either a local wastewater utility, a state environmental agency, or a U.S. EPA
Regional Office.
	If your dental facility is in Alabama, Connecticut, Mississippi, Nebraska or Vermont: your Control
Authority is your state agency. Contact information for each state is available at
www.epa.gov/npdes/contact-us-national-pretreatment-program (select the "State Agency Contacts"
tab).
	For dentists in all other states: contact your U.S. EPA Regional Office, your local wastewater utility, or
your state agency Pretreatment Coordinator to identify your Control Authority. Pretreatment contact
information for EPA headquarters, EPA Regions, and state agencies is available at
www.epa.gov/npdes/contact-us-national-pretreatment-program (select the appropriate tab).
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My practice is in compliance with the standards in the rule and has submitted a one-time compliance
report. It is now changing ownership. Do I or the new owner need to submit a new one-time compliance
report?
Yes. If a dental discharger transfers ownership of the facility, then the new owner must submit a new one-time
compliance report to the Control Authority. See above for compliance deadlines and  441.50(a)(4).
Is there a website where I can submit my one-time compliance report electronically?
Check with your Control Authority.
Does the final rule prohibit the use of oxidizing or acidic cleaners in dental unit water lines, chair-side traps,
and vacuum lines?
Yes. The clause that follows ("including but not limited to...") is not an exhaustive list of oxidizing or acidic
cleaners or qualities that make a cleaner oxidizing or acidic. For example, a cleaner that is oxidizing would be
prohibited even if its pH is between 6 and 8.
Does the prohibition on the use of oxidizing or acidic cleaners in dental unit water lines apply to cleaners
used in the water supply lines that connect to items such as handpieces, ultrasonic scalers or air/water
syringes?
No. The purpose of the best management practice (BMP) specified in  441.30(b)(2) is to prohibit the use of
cleaners that solubilize mercury from dental amalgam in the wastewater lines in a dental facility. In developing
the rule, EPA did not evaluate the use of cleaning products that may be used in dental equipment that is
connected to water supply lines such as handpieces, ultrasonic scalers, or air/water syringes. While de
minimus amounts of such products may eventually be indirectly discharged through a wastewater line in a
dental facility, the prohibition in  441.30(b)(2) was not intended to prohibit dental unit water line cleaning
products when those products are used in water supply lines to ensure the safety of the water that dentists
place in their patient's mouth.
Is the amalgam collected in the separator considered a hazardous waste under the Resource Conservation
and Recovery Act (RCRA)?
Yes. The amalgam collected in a separator is likely to be a hazardous waste under RCRA due to the mercury
and silver content of the amalgam. However, dental offices producing less than 100 kg of hazardous
waste/month AND less than 1 kg of acute hazardous waste per month are considered "Very Small Quantity
Generators" (VSQGs are regulated under  262.14) and are exempt from most RCRA requirements for the
disposal of their hazardous waste (Note that VSQGs were formerly called "conditionally exempt small quantity
generators" (CESQGs) but were renamed in November 2016). EPA generally does not expect dental offices
collecting amalgam waste to be above the VSQG threshold.
A generator must count all of the hazardous waste it generates in a calendar month, not just the amount of
amalgam, to determine what RCRA generator category is appropriate. If you believe you may qualify as a
"Small Quantity Generator" (dental office that produces 100-1000 kg of hazardous waste per month AND less
than 1 kg acute hazardous waste per month) or a "Large Quantity Generator" (dental office generates more
than 1000 kg of hazardous waste per month OR more than 1 kg of acute hazardous waste per month), please
contact your state hazardous waste authority to understand your requirements for the management of
hazardous waste. Links to state environmental agencies are on EPA's website at
www.epa.gov/hwgenerators/links-hazardous-waste-programs-and-us-state-environmental-agencies
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What about state and local requirements?
The EPA rule is a floor (i.e. a minimum requirement), not a ceiling, for regulating discharges of dental office
wastewater to POTWs. There may be additional requirements under state or local law that go beyond those
EPA's Dental Office Category Rule.
Where can I find more information?
The Federal Register notice for the rule, along with other information, can be found on EPA's Effluent
Guidelines website at www.epa.gov/eg/dental-effluent-guidelines.

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