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Dental practices that discharge waste material into the King County sewage system must be in compliance with the county discharge limits and Environmental Protection Agency (EPA) regulations .

New Regulation: In July 2017, the EPA published new regulations for dental offices in the Code of Federal Regulations, 40 CFR Part 441 . (See exempted specialties below.)

Dentists must (click each item below to learn more):

Where to send your compliance report :

  • If your office is located in the purple area on the KCIW compliance area map, send your compliance report to King County Industrial Waste at the address on the report.
  • If your office is located outside of the purple area on the KCIW compliance area map, send your report to WA State Dept. of Ecology, Water Quality Program at the address on the report.

Deadline for sending the compliance report:

  • October 12th, 2020 for existing offices.
  • Within 90 days, if the office is transferred to a new owner after July 14, 2017. KCIW also requests that you contact them to update your practice's contact information.
  • New offices should submit the report no later than 90 days following the introduction of wastewater into the sewer. 
  • 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 sewer system.
  • Dental unit water lines, chair-side traps, and vacuum lines that discharge amalgam process wastewater to a sewer system 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.

Who does this new regulation apply to?

Most dental offices in King County’s compliance area already have installed approved amalgam separator units. These offices, including endodontists and some pediatric specialties, need to submit a one-time compliance form.

These specialties do not need to fill out a compliance form:

  • Oral pathology
  • Oral and maxillofacial radiology
  • Oral and maxillofacial surgery
  • Orthodontics
  • Periodontics
  • Prosthodontics dentists using a mobile unit
  • Dentists that that do not discharge any amalgam process wastewater to one of King County’s wastewater treatment plants (such as dental dischargers that send all dental amalgam process wastewater to a Centralized Waste Treatment facility as defined in 40 CFR part 437 )

King County Industrial Waste Compliance Area

Enter your business address (including City) into the search box to determine if your dental practice is in the compliance area. 

We know that the industrial waste authorization and application process is complex. Please contact us if you have questions and our staff will be happy to assist you. If you have difficulty viewing or downloading documents, please visit Software Help.

Update your practice's contact information

Is yours a new dental office - or have you recently relocated your office within King County? Please contact KCIW and provide the following information:

  • name
  • name of practice
  • address
  • phone and
  • business e-mail.


An amalgam separator takes the mercury and other pollutants out of the water that goes down the drain in the dentist’s office. This way both the pollutants and the water can be treated properly to protect the environment.

Mercury dropped significantly in the recycled products from King County’s wastewater treatment plants after we began working with dentists to install amalgam separators in 2000.

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