Dental Offices

It is illegal to allow anything other than rain water to be discharged to a storm drain.

The two biggest pollutants of concern coming from dental offices are mercury and silver.  Vacuum lines, sinks and toilets all lead to local sewer lines, so anything you pour down the drain goes to a Treatment Plant and has a potential to be discharged.  Because Treatment Plants may not be designed to remove metals like mercury and silver, control of any discharges is required.  If spilled or disposed of improperly these contaminants can harm the public and local aquatic life and health.

Individuals and businesses that improperly handle and dispose of materials are both subject to civil and criminal prosecution.

Wastewater Discharge Permit Requirements

All dental practices are required to install an amalgam separator unless the conditions for exemption are met.

  • Check your local jurisdiction for discharge requirements.
  • For proper disposal questions on hazardous materials and recycling call the Eco-Desk at (707) 565-DESK (3375), or visit
  • For more information about obtaining a Wastewater Discharge Permit in the cities of Santa Rosa, Rohnert Park, Sebastopol, and Cotati call (707) 543-3369 or visit


Conditions for Exemption

A facility may be exempt from installing an amalgam separator if amalgam fillings are removed or placed three (3) or fewer days per year and the facility serves the following primary function:

  • Orthodontics
  • Periodontics
  • Oral and maxillofacial surgery
  • Radiology
  • Oral pathology or oral medicine
  • Endodontics
  • Prosthodontics

Best Management Practices (BMPs)

  • Maintain amalgam separator as needed.
  • Use pre-capsulated amalgam.  Discontinue use of bulk liquid mercury.
  • Change chairside traps frequently.  Store traps and contents as amalgam waste.  Never rinse traps in the sink.
  • Change wet vacuum pump screen as needed.  Seal plastic container and all contents with screen and store with amalgam waste.  Never rinse contents down the drain.
  • Segregate amalgam-containing waste.  Do not include with medical “red bag” waste, regular solid waste, or general office recycling containers.  Red bag waste is especially problematic as a receptacle for amalgam waste as it is generally incinerated, which volatilizes mercury.  Store amalgam waste in air-tight containers, following your waste hauler’s instruction.
  • Properly dispose of x-ray fixer using a licensed waste hauler.  Never pour fixer down the sink.
  • Avoid bleach and other chlorine-containing products when cleansing vacuum system.
  • Train staff in the proper handling and disposal of amalgam and x-ray waste.  Maintain a training log.
  • Maintain disposal logs for amalgam and x-ray fixer waste.

Become a Pollution Prevention Partner

  • The City of Santa Rosa Environmental Compliance Section inspects dental practices every three years.  If the inspection shows that the office is in compliance with their Wastewater Discharge Permit, as well as the required Best Management Practices from the City Sewer Code Title 15.08.567, then the dental practice will be acknowledged as a Pollution Prevention Partner.
  • As a Pollution Prevention Partner the practice will receive a certificate and be listed on our website.

Releasing pollutants into the storm drain system or a waterway is prohibited by local ordinance, state, and federal law.

How are the Storm Drain and Sanitary Sewer Systems Different?

Throughout urban communities, the storm drain system transports rainwater to local creeks, rivers, and the ocean. This system was created to prevent flooding within communities and homes.

All water and materials that enter the storm drain system is untreated.

The sanitary sewer is a plumbed system that transports used water from buildings to a wastewater collection and treatment facility, where the water and sewage is treated.

If you see an outdoor drain and are unsure of its use, assume it is a storm drain and do not discharge wash water to it.

If spilled material contains hazardous materials call 911.

For all other non-hazardous spills, that has potential to impact the storm drain system,

Report Spills Here

Cloverdale: (707) 894-2150
Cotati: (707) 665-3605
Healdsburg: (707) 431-7000
Rohnert Park: (707) 588-3300
Santa Rosa: (707) 543-3800,
After Hours: (707) 543-3805
Sebastopol: (707) 823-5331,
After Hours: (707) 829-4400
Ukiah: (707) 463-6288
Unincorporated County of Sonoma: (707) 565-1900
Unincorporated Mendocino County: (707) 234-6679
Windsor: (707) 838-1006,
After Hours: (707) 838-1000

Have you seen this in your neighborhood?