Subsurface Wastewater Discharge Program

Related program


Each year Mainers generate LARGE amounts of wastewater.  Wastewater produced by ordinary living uses, including liquid waste from toilets, washing machines, sinks, and other human origins is known as domestic wastewater.  Most homeowners dispose of their domestic wastewater through their municipal wastewater treatment plant or in on-site septic systems.  

Some businesses in Maine, however, produce wastewater that has constituents unlike those found in domestic wastewater or constituents of significantly higher strength than what would be found in domestic wastewater.  This type of wastewater is known as non-domestic wastewater.  Much of this wastewater is disposed of through DEP-licensed wastewater treatment facilities.  But, some businesses -- either because of their location or the nature of their wastewater -- consider on-site, subsurface wastewater disposal.

If disposed of improperly, non-domestic wastewater has the potential to contaminate ground water.  More than 60% of Mainers rely on ground water for some or all of their drinking water and that number rises to greater than 90% in rural areas.  In addition to its use as drinking water, ground water feeds our lakes and help recharge our streams and rivers, particularly during dry periods.  Preventing ground water contamination in vital to protecting the drinking water of Maine citizens and to maintaining the quality of our lakes, streams and rivers.


This website has been designed to be your first stop on the path to compliance. 

  • Questions about whether your particular waste stream is suitable for subsurface disposal or information on applying for a waste discharge license should be directed to Cindy Dionne at 207-446-3820. 
  • Questions about floor drains, holding tanks, the UIC Program or registering your Class V well should be directed to Laura Crossley.


The Department of Environmental Protection is responsible for licensing or otherwise regulating the subsurface disposal of non-domestic wastewater in Maine.  The subsurface wastewater discharge program is a combination of activities related to ground water protection, including:

  • Issuing waste discharge licenses for some types of subsurface wastewater disposal, such as the subsurface wastewater disposal of domestic wastewater by municipalities and the disposal of wastewater from automatic car washes, some food processors and public drinking water treatment filtration systems;
  • Inspecting floor drain connections at automobile dealerships, repair garages and other gasoline- and diesel-engine repair facilities to ensure proper and legal floor drain connections; and
  • Administering the Underground Injection Control (UIC) Program in Maine.  The UIC Program, authorized by the Safe Drinking Water Act, requires owners of some types of subsurface wastewater disposal systems to register their systems with the Department of Environmental Protection.

Related Program

Disposal of domestic wastewater (other than by a municipality) is regulated by the Department of Human Services, Wastewater and Plumbing Control Program and implemented at the municipal level by local code enforcement officers and site evaluators. 

  • For information about the on-site subsurface disposal of domestic wastewater, contact Alex Pugh, 287-5695 or Brent Lawson, 592-7376.