Massachusetts Industrial Wastewater Holding Tanks: What Facilities Should Know About 314 CMR 18 Compliance

Author: Shawn Murphy

Industrial wastewater holding tanks are common across many industries throughout Massachusetts. Yet many facility owners are unaware that these systems may be subject to specific regulatory requirements under Massachusetts Department of Environmental Protection (MassDEP) regulation 314 CMR 18.00.

For facilities that temporarily store non-hazardous industrial wastewater before off-site treatment, recycling, or disposal, compliance involves more than arranging routine pump-outs. Facilities that have not recently reviewed these systems may be carrying avoidable compliance risk.

What Is 314 CMR 18?

MassDEP’s 314 CMR 18.00 – Industrial Wastewater Holding Tank and Container Construction, Operation, and Record Keeping Requirements – was developed to protect public health and the environment by regulating industrial wastewater storage prior to off-site recycling, treatment, or disposal. The regulation establishes requirements for system design, operation, compliance certification, recordkeeping, and decommissioning procedures for vessels that store industrial wastewater, including aboveground tanks, in-ground tanks, mobile tanks, and containers.

Does 314 CMR 18 Apply to Your Facility?

Applicability is based on how wastewater is managed – not simply whether a tank, mobile tank, or container exists. The regulation applies when all three of the following criteria are true:

• The vessel is used exclusively to accumulate or store industrial wastewater generated on-site or off-site
• The wastewater in the vessel will be transported directly to an off-site facility for recycling, treatment, or disposal
• The wastewater is considered non-hazardous, non-domestic industrial wastewater.

Common examples of non-hazardous, non-domestic industrial wastewater include process wastewater, equipment cleaning wastewater, vehicle wash water, floor drain collection systems, and spent solutions from industrial cleaning operations. Industries frequently affected include manufacturing, metal finishing, laboratories, food and beverage, hair salons, vehicle maintenance, pharmaceutical, and biotechnology.

Note: 314 CMR 18 does not apply to tanks that transfer wastewater between production processes or treatment systems, or to tanks that hold wastewater prior to discharge to a municipal sewer system. Hazardous waste tanks, Title 5 tight tanks, and tanks used exclusively to hold non-contact cooling water or heating/cooling condensate are also exempt.

Design and Operational Requirements Vary

Requirements differ depending on the type of holding tank system in use – one of the most important compliance considerations facilities should understand.

Aboveground holding tanks must include level monitoring, secondary containment, labeling, and odor control measures necessary to prevent nuisance conditions. Systems that are remotely or automatically filled also require alarm systems to reduce overflow risk.

Note: Aboveground holding tanks fabricated on-site must be constructed in accordance with engineering plans stamped and signed by a Massachusetts registered Professional Engineer (PE). This requirement does not apply to prefabricated tanks, such as plastic tanks.

In-ground holding tanks are subject to more stringent requirements due to the increased potential for undetected leaks and groundwater impacts. In-ground tanks must be sized to accommodate greater than 500% of the average daily flow generated from the facility and designed to withstand the American Association of State Highway and Transportation Officials (AASHTO) H-20 loading if installed completely below ground. Additional requirements include level monitoring and alarm systems, labeling, odor control, secondary containment, leak detection, and recurring inspections.

Note: In-ground holding tanks are required to be constructed in accordance with engineering plans stamped and signed by a Massachusetts registered PE.

Compliance Certification

Tank systems that meet the applicability criteria must adhere to the applicable design and operational requirements outlined in 314 CMR 18.00 and submit a one-time compliance certification to MassDEP within 60 days of installation for each tank, in accordance with the Environmental Results Program (ERP) Certification regulations at 310 CMR 70.03.

Submitting a compliance certification involves completing the MassDEP provided WP56 Compliance Certification form. The certification requires the facility to confirm that the tank system meets the applicable design and operational requirements under 314 CMR 18 and is required to be uploaded as an attachment when filing the certification through the MassDEP EEA ePLACE Portal.

Note: The one-time compliance certification requirement does not apply to mobile tanks and containers. However, mobile tanks and containers must still adhere to all applicable design, operation, and recordkeeping requirements outlined in the regulation.

Recordkeeping is a Key Compliance Driver

314 CMR 18 compliance extends beyond physical design and operational conditions – documentation requirements are equally important.

Engineering plans, including holding tank design and construction specifications (stamped and signed by a Massachusetts PE, if applicable) must be maintained at the facility for the life of the tank until decommissioning. Facilities should also check local municipal board of health requirements, as 314 CMR 18 requires facilities to obtain and maintain any applicable permits or written approval from the local municipal approving authority.

Facilities are also required to maintain three years of operating and hauling records, including the date, volume, and description of each shipment, receiving facility documentation, and the name and vehicle registration of the wastewater hauler. These records are frequently requested during inspections, audits, environmental due diligence reviews, and property transactions.

Common compliance gaps identified during environmental reviews include missing engineering plans, missing secondary containment, incomplete shipment records, inadequate labeling, missing level alarms, undocumented modifications, and legacy tanks that were never evaluated against current requirements.

What Should Facilities Do Now?

Facilities should take time now to evaluate whether existing wastewater storage practices comply with current regulatory requirements. Specific steps include:

• Confirming applicability under 314 CMR 18
• Reviewing design and operational procedures
• Reviewing available engineering plans
• Assessing inspection and recordkeeping programs
• Evaluating spill prevention measures
• Determining whether aging infrastructure warrants additional review

Proactive evaluations can reduce regulatory risk, improve operational reliability, and prevent surprises during inspections or future facility changes.

How ALL4 Can Help

ALL4 supports facilities throughout Massachusetts with industrial wastewater holding tank applicability reviews, compliance evaluations, engineering documentation, compliance certification, regulatory strategy, and long-term environmental management planning.

Whether your facility is evaluating an existing holding tank system, planning upgrades, responding to inspection findings, or determining applicability under 314 CMR 18 for the first time, we can help identify practical next steps and support implementation. Please contact Shawn Murphy at smurphy@all4inc.com for assistance.