Fact Sheet: Industrial Floor Drains and Groundwater Quality

Floor drains in industrial and commercial settings can cause significant contamination if used improperly. While many industries have begun investing in cleaner technologies, floor drains remain an easy method of disposing of wash water that may contain small concentrations of hazardous or toxic chemicals. Floor drains may be plumbed to a municipal sewer line, or they may just lead to a subsurface disposal point. When floor drains discharge to soil, the drain, the pipes and all associated structures for conveyance of wastewater to soil are called a shallow injection well.

A shallow injection well includes any subsurface excavation, such as a drywell, seepage pit, septic system, leach field, or unlined sump, through which waste water is disposed below ground.

Used or spilled fuel, solvents, waste oil, paints, and other maintenance fluids pose a risk to the environment but may be especially harmful if they enter someone's drinking water supply. Floor drains at facilities which use these substances should be evaluated. Facility managers should know if floor drains and other drains from sinks, toilets, showers etc. lead to a municipal sewer line, to a surface discharge, or to a shallow injection well.

Shallow injection wells allow waste to percolate into soil. Because of their potential to contaminate underground sources of drinking water, they are regulated through the U.S. Safe Drinking Water Act, Underground Injection Control (UIC) regulations. Owners and operators of shallow injection wells are usually not required to obtain a federal permit, but are required to submit inventory information to their state or federal Underground Injection Control (UIC) programs so that actions can be taken where necessary to prevent contamination of underground sources of drinking water. UIC programs have the authority to request additional information about particular wells, or require a permit if there is a risk of contamination from a facility. State and local programs may have more stringent permitting requirements than the federal regulations.

Some types of industries have higher incidences of soil and ground water contamination than others. So some state and EPA UIC programs have permits or other requirements for those particular industries or types of waste discharge. For example, the construction of new motor vehicle waste disposal wells is banned effective April 5, 2000 (nationwide) because of the potential for such wells to discharge fuel and motor repair fluids to the ground. Existing motor vehicle waste disposal wells may be required to close or meet conditions of a discharge permit.

When the motor vehicle waste disposal well regulations were proposed, EPA also proposed additional regulations for shallow injection wells receiving industrial waste. Those regulations have not been adopted, but could apply in the future.

To help business owners and facility managers assess their environmental liability and comply with ground water protection regulations, EPA has prepared this information to accompany the Inventory of Injection Wells form. In order to be authorized to operate an injection well, owners or operators of injection wells are required to submit this information to EPA or to the delegated Underground Injection Control Program in their state.

Evaluating Floor Drains

Here are steps to determine whether or not a facility uses Class V shallow injection wells:

  • Identify all floor drains and other possible points of entry to subsurface pipelines in hazardous material use/storage areas, fueling areas, wash bays, or industrial process areas.
  • For each drain, identify the drain's final point of discharge. This may be achieved by presentation of sewer or holding tank permits, or stamped, "as-built" plans, by performing dye or smoke tests, looking at the pipe using downhole cameras, reviewing records of tank pumping, or simply by examining the floor drain grates or popping separator or sewer manhole covers.
  • If no absolute determination can be made as to where a pipe ends, or if you determine that it ends with disposal to soil, you have a shallow injection well.
  • Comply with the inventory requirement. (for more information, go to http://www.epa.gov/safewater/uic/classv.html) EPA will share the information with the appropriate state and local agencies, who may get back to you about your well.

Other Risk Factors:

  • Present activities. Does facility manage hazardous materials, particularly solvents & other volatile compounds? (Examples: dry cleaner, auto body shop, metal plating) How are potentially hazardous fluids prevented from entering a floor drain? What spill containment practices are used?
  • Historic Activities. Were any former occupants of the site likely to have disposed hazardous or toxic waste to floor drains?
  • Proximity to ground and surface water: How far is it to the nearest private or public drinking water well? How far is it to the nearest creek, river, lake or shore?
  • Operations Permits. Do any permits you have on file with the local building or health department require you to monitor discharges to your floor drain?
  • Sampling. Have you ever had the sludge below the drain analyzed by an environmental laboratory for toxic or hazardous constituents?

For more information on Class V shallow injection wells, go to http://www.epa.gov/safewater/uic/classv.html.

Also see the Web page for EPA Compliance Assistance Centers (http://es.epa.gov/oeca/main/compasst/compcenters.html), which has links to assistance for these specific industries: automotive service, chemicals, local government, metal finishing, paints and coatings, printed wiring boards, printing and transportation.

Fact sheet from EPA.

This article originally appeared in the 03/01/2006 issue of Environmental Protection.

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