Introduction
Sanitary wastewater discharges are regulated by the Washington Suburban Sanitary Commission (WSSC) and the Maryland Department of the Environment (MDE) establish specific conditions under which wastewater can be discharged. Below are general regulatory requirements for wastewater discharge and identifies compliance management practices for facility and staff personnel.
Applicable University Policy
University of Maryland, Environmental, Safety and Health Management Policy.
Applicable Regulation
- 2024 WSSC Plumbing and Fuel Gas Code, Chapter 8, Industrial and Special Waste, especially Sections 803–806 and Section 804.1, including Table 804.1.9. This edition took effect December 1, 2025.
- 40 CFR Part 403, General Pretreatment Regulations for Existing and New Sources of Pollution, especially Section 403.5, which establishes federal prohibitions on discharges to publicly owned treatment works.
- COMAR 26.08.08, Pretreatment, including the State Pretreatment Program requirements. This is the relevant Maryland regulation for pretreatment; COMAR 26.04 is not the applicable citation for WSSC industrial sewer discharges.
- COMAR 26.08.04, Permits, and applicable MDE permit conditions apply when wastewater is discharged to surface waters. A WSSC sewer authorization does not authorize a discharge to a storm drain, stream, or other State water.
Summary of Requirements
General: WSSC regulates non-domestic wastewater discharged to its sanitary sewer system. University activities that generate wastewater must comply with the WSSC Plumbing and Fuel Gas Code and any applicable WSSC Discharge Authorization Permit (DAP). WSSC determines whether a DAP is required. The permit may set discharge limits, pretreatment requirements, sampling and reporting schedules, and other conditions. The most stringent applicable federal, State, local, or permit requirement must be met.
At UMD, wastewater containing volatile organic compounds (VOCs), metals, or unusually acidic or caustic materials requires particular care. Do not dispose of chemicals or process wastewater to a drain unless the discharge is allowed under the applicable requirements and permit.
Key prohibited discharges: The following must not be discharged to the WSSC sanitary sewer:
- Wastewater with a pH below 6.0 or above 10.0. The pH may not be below 5.0 at any time.
- Liquids or vapors hotter than 140°F. A discharge also may not raise the temperature at the treatment plant influent above 104°F.
- Materials that could cause a fire or explosion, including wastewater with a closed-cup flash point below 140°F or a combustible-gas reading above 5% of the lower explosive limit.
- Toxic or malodorous gases, vapors, fumes, or other substances that could create a nuisance or health or safety hazard.
- Materials that could damage or block sewer pipes, interfere with sewer or treatment plant operations, pass through treatment, or cause the treatment plant to violate its permit. This includes harmful concentrated or sudden releases.
- Stormwater, surface water, groundwater, roof runoff, or subsurface drainage.
- Petroleum oil, non-biodegradable cutting oil, or mineral-oil products in amounts that could interfere with treatment or pass through the plant.
- Radioactive or disease-causing wastes that exceed applicable limits or could create a health hazard.
- Glycol used in engine-cooling or liquid-conveyance systems to change the freezing or boiling point.
- Trucked or hauled pollutants, except at WSSC-designated disposal points.
WSSC’s current Table 804.1.9 sets numerical limits for specific metals, solvents, PCBs, and other wastewater parameters. The table includes limits for arsenic, cadmium, chromium, copper, cyanide, lead, mercury, molybdenum, nickel, selenium, silver, zinc, tetrachloroethylene (PCE), trichloroethylene (TCE), total PCBs, ammonia, solids, BOD, phosphorus, oil and grease, pH, and temperature. Consult the WSSC Code and any applicable permits for the specific limits, as they may be more stringent.
Other wastewater: Non-contact cooling water, industrial process wastewater, filter backwash, and hazardous waste are not all blanket-prohibited by name in WSSC Section 804.1. Their discharge may still be restricted by the Code and other applicable requirements. Check with the Office of Environmental Affairs and obtain any required WSSC authorization before discharging these or other non-domestic wastewaters to the sanitary sewer.
Discharges to surface waters: Wastewater or industrial stormwater discharged to a stream, storm drain, or other surface water may require separate MDE authorization. Do not use a storm drain for wastewater disposal.
Training
University personnel whose work could affect wastewater discharges should know which drains connect to the sanitary sewer, what materials are prohibited, and how to report a spill or other discharge concern to ESSR.
If WSSC requires a slug-control plan, the plan must include spill-prevention and response procedures, employee training, and instructions for notifying WSSC. Employees who could cause or be affected by a dangerous discharge must be informed of the emergency notification procedure.
Reporting
Immediately notify ESSR of any spill, accidental release, slug discharge, or other condition that could cause a problem in the sewer system or violate a discharge requirement. ESSR will coordinate the required notification to WSSC and any written follow-up.
WSSC’s deadlines depend on the type of event. For example, a self-monitoring result showing a violation of a WSSC limit must be reported directly to WSSC within 24 hours of becoming aware of it. The violation data and explanation are due within seven days, and repeat sampling is generally due within 30 days. A slug discharge or other potential problem may require immediate notice and written follow-up within five days under an applicable slug-control plan. Follow the WSSC permit and ESSR instructions for the specific event. A message left on WSSC’s recording system alone does not satisfy the 24-hour violation notification requirement.
Notify ESSR as early as possible about planned process or operational changes that could affect the volume or characteristics of wastewater discharged.
Inspections and Maintenance
WSSC may inspect University facilities, review records, and monitor or sample wastewater at any time, including when a facility is operating, discharging, or could discharge. University personnel must provide access to relevant areas and equipment.
Operate and maintain pretreatment systems, sampling equipment, and monitoring devices according to the applicable WSSC permit, approved plans, and manufacturer instructions. Calibrate monitoring equipment as required by the manufacturer.
Recordkeeping
Keep records related to wastewater discharges for at least three years from the date they are prepared. Records may include sampling and monitoring results, analytical reports, pretreatment system operation and maintenance logs, calibration records, spill documentation, and required best management practice records.
Keep records longer if they relate to a WSSC order, enforcement action, or legal proceeding. Additionally, records should be made available to WSSC upon request.