Wellhead Protection Guide - Floor Drain Discharges

Commercial and industrial floor drains discharging directly to the ground or via septic systems, cesspools, leaching fields or dry wells, pose a serious threat to public drinking water quality. In Massachusetts, floor drain discharges have caused groundwater and soil contamination, resulting in lengthy and costly remediation.

Table of Contents

Local Requirements

To address these discharges, MA Drinking Water Regulations require a local prohibition on existing floor drain discharges in Zone II of public drinking water wells.  Specifically, MA Wellhead Protection Regulation 310 CMR 22.21(2)(a)(8) prohibits: any floor drainage systems in existing facilities, in industrial or commercial hazardous material and/or hazardous waste process areas or storage areas, which discharge to the ground without a MassDEP permit or authorization.  Existing facilities  with  such a drainage system shall be required to either seal the floor drain (in accordance with the state plumbing code, 248 CMR 10.00), connect the drain to a municipal sewer system (with all appropriate permits and pre-treatment), or connect the drain to a holding tank meeting the requirements of all appropriate MassDEP regulations and policies.

Benefits of Having a Local Control

Once a floor drain control is adopted a municipality can establish a local floor drain inspection program. Such programs are usually implemented by the Board of Health or the Building or Plumbing Inspector.  Inspections can be streamlined by prioritizing facilities located in a Zone II, and conducting inspections over a phased period of time. See ‘Tips for Implementing a Successful Floor Drain Prohibition’ below.  Additionally MassDEP’s ‘Sample Board of Health Floor Drain Letter’ can be used to notify business of an upcoming inspection and the steps they must take to meet compliance.  A local program can also be used to provide technical assistance to businesses having difficulty achieving compliance.

Additional Resources for Benefits of Having a Local Control

How the Plumbing Code Differs

The Drinking Water Program is often asked why the Plumbing Code, 248 CMR 10.00, cannot be used to satisfy the floor drain prohibition 310 CMR 22.21(2)(a)(8).  The reason is because the Plumbing Code is limited in scope. It applies only to those activities that 'produce oily or liquid hazardous wastes'.    In contrast, the floor drain prohibition includes these facilities and facilities which also 'store hazardous wastes or hazardous materials’. A local floor drain control, meeting 310 CMR 22.21(2)(a)(8), is thus a more stringent and comprehensive control.

Tips for Implementing a Successful Floor Drain Prohibition

  • Prioritize Inspections
    • If the local floor drain regulation applies to the entire municipality, prioritize facility inspections in the Zone II, then phase in facilities outside the Zone II.
    • Develop an inspection list.  If the regulation applies to just the Zone II, prioritize facilities that have not recently been inspected, or have other regulatory concerns.
    • Enlist the aid of the building and/or plumbing inspector in identifying facilities with existing floor drains in the Zone II (building modifications and change of use often require inspections).  
  • Send Facilities a Letter
    Inspections should serve as the primary vehicle to implement the floor drain prohibition.  Prior to inspections it can be helpful to inform facilities of the newly adopted floor drain regulation, an upcoming inspection, and the information they must have on hand for the inspection.  MassDEP designed ‘A Sample Inspection Letter ‘ to assist local entities with notifying businesses (included in this guide).
  • Conduct Inspections
    • Provide businesses with a map indicating the location of their facility with respect to the drinking water well and their location in (or near) the Zone II;
    • Determine if floor drains are present in the hazardous material or hazardous waste process or storage areas of the facility.  These are the areas where floor drains are prohibited.  If a floor drain is located, determine the ultimate discharge point of the drain.
      • Sewer Connection - Verify the discharge of a drain to the municipal sanitary sewer line by either seeing "as-built" diagrams or municipal own or state sewer connection records; or through the use of field efforts, such as a dye test, metal detector survey or drain line inspection camera.
      • Holding Tank - Verify the connection of a drain to a holding tank by seeing MassDEP holding tank permit records.
      • Oil/Water Separators - These are designed to have a discharge. Unless specifically converted with MassDEP approval, these are not considered holding tanks. If an oil/water separator is in use (they must be used by some facilities such as auto repair garages with drains tied to the sanitary sewer line) determine if the facility obtained MassDEP approval of conversion to a holding tank. 
  • If it is determined that the facility is subject to the floor drain prohibition, notify the facility of the results of the inspection, and the steps they must take to comply with the local floor drain prohibition.
  • To verify if a facility has a valid Ground Water Discharge Permit, contact MassDEP at 617-556-1029, The Groundwater Discharge Permitting Program.
  • For information about floor drain discharges, contact the Underground Injection Control Program at 617-292-5859, Underground Injection Control Program.

Additional Resources for Tips for Implementing a Successful Floor Drain Prohibition

Image credits:  Detail View of Basement Floor Drain (Library of Congress)

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