Mason MS4 Program

Mason’s Municipal Separate Storm Sewer System (MS4) permit is mandated by Clean Water Act and by EPA stormwater regulations. Virginia Department of Environmental Quality (DEQ) administers MS4 permits as part of the Virginia Stormwater Management Program permit program. Masons MS4 permit covers Fairfax Campus at Fairfax County and Science and Technology Campus at Prince William County.

Mason’s MS4 Permit requires Mason to comply with the conditions set forth in the permit. These conditions include six minimum control measures (MCMs), TMDL special conditions and general conditions.

TMDL Special conditions

A Total Maximum Daily Load TMDL for the Chesapeake Bay was established by the U.S. Environmental Protection Agency (EPA) in 2010 requiring states and localities to remove specific pollutants from storm water runoff before the water enters local streams and rivers that drain into the Chesapeake Bay. The level of pollutants allowed to be discharged to the Chesapeake Bay is called a Total Maximum Daily Load (TMDL).

Mason is required to develop Chesapeake Bay TMDL Action Plans that show how Mason intends to meet the three milestones: a 5 percent reduction in nitrogen, phosphorus and suspended solids by June 30, 2018. Mason will be required to offset an additional 35% reduction by June 30, 2023, and the final 60% by June 30, 2028.

Mason has developed and implemented the first TMDL Action Plan and exceeded the 5% reduction goal.

Mason is in process to develop second TMDL Action Plan to meet the 35% reduction goal by 2023.

MCM 1: Public Outreach and Education

The MS4 program at George Mason University (Mason) seeks to alert residents, students, faculty, and staff members on the impacts of stormwater runoff on water quality through free training sessions, workshops, signages, and the distribution of educational materials. The public outreach program at Mason also provides guidance on how the community can help in minimizing adverse impacts of urban runoff in waterways.

  • Schedule of events and workshops

Additional Resources

MCM 2: Public Involvement and Participation

Mason encourages residents, students, faculty, and staff members to participate in volunteer programs hosted on campus for the conservation and improvement of water resources. Projects such as the Patriot Pack Out and Campus Cleanups, Storm Drain Marking, etc are conducted on regular basis with the purpose of getting the community involved in the Mason’s efforts on reducing the amount of pollutant loads in stormwater. Mason LD also works with student residents to maintain and beautify rain gardens around the campus.

In addition, Educational workshops and materials, offered by Mason, also provide information to the public about stormwater management practices implemented on campus and different sustainable practices that can help restore and protect our water.

MCM3: Illicit Discharge Detection and Elimination

In order to detect and eliminate both direct and indirect illicit discharges, Mason has developed an Illicit Discharge Detection and Elimination Program (IDDE), which relies on the Mason’s Illicit Discharge Detection and Elimination Policy to prohibit any non-stormwater discharges into the stormsewer system or any receiving waterway.  The policy is enforced by both, Mason LD and the Environmental, Health and Safety Office (EHS), who rely strongly on regular inspections and public notification. Mason encourages the community’s contribution in discovering and reporting possible polluted runoff and maintains appropriate staffing to address such reported concerns.  If you would like to report suspected non-stormwater discharges, fill out an Illicit Discharge Report Form, and/or email us at .

Outfall Reconnaissance Inventory (ORI) is another important component of the IDDE program at George Mason University. The ORI is performed bi-annually in order to identify possible illicit connections and discharges, as well as, to keep track of all existing stormwater management facilities and structures within Mason. During the ORI, outfalls are also evaluated for structural damages or uncommon conditions that might indicate the present of pollutants.

In the event of an oil or chemical spill, follow the Petroleum and Chemical Spill Response and Remediation or contact the Environmental Health and Safety Office (EHS)

Indicators of Potential Illicit Discharge

  • Unusual color or cloudiness
  • Unusual odor
  • Turbidity or muddy water
  • Dead vegetation or excessive vegetation
  • Floatables
  • Pipe corrosion
  • Surface scum or foam
  • Stains on channel bottom, sides and/or outfall rocks
  • Oil sheen
  • Dead animals

MCM4: Construction Site Stormwater Runoff Control

Under the VSMP permit, George Mason University is required to develop, implement and enforce a program to reduce the discharge of pollutants associated with construction activity into the MS4. Mason has developed Annual Standards and Specifications for ESC and SWM, which is an integral component of project design, construction, maintenance, and management of Mason’s facilities and campuses. Mason’s Annual Standards and Specifications for ESC and SWM is submitted to Virginia DEQ for review and approval on an annual basis.

Mason LD personnel receive training by DEQ on Erosion and Sediment Control and Stormwater Management to enforce such programs.  Certified staff is responsible for reviewing plans during the permitting process, and conducting regular inspections of the site during construction.

Public concern associated with runoff from construction activities can be sent to Mason LD via email at

MCM5: Post Construction Stormwater Management

Stormwater Best Management Practices (BMPs) are engineered facilities that convey storm runoff, remove pollutants and to control flow rates. They are designed to improve the stormwater runoff quality that reaches the Chesapeake Bay and helps preventing flooding. Mason implements both structural and non-structural BMPs to manage and control stormwater and to promote natural hydrologic processes. As land disturbing activities take place, Mason incorporates measures that protect and/or improve natural areas during and after construction. In addition to the ongoing efforts to preserve the natural landscape, Mason strives to reduce impervious areas as much as possible and create more vegetated regions.

Non proprietary BMPs

Mason’s Vegetated Roofs:

Mason’s Vegetated Roofs

In 2006, George Mason University constructed its first vegetated roof located on the Fairfax campus, outside of Research I building. The facility covers an area of approximately 1030 ft filled with a variety of hardy and aesthetically pleasing plants that seamlessly blend into existing landscaping. The filtration properties of this facility help to eliminate pollutants while reducing storm water runoff.




Porous Pavement at Mason Vale

Porous Pavement at Mason Vale:

In the ongoing effort to reducing impervious areas, Mason continues to encourage the implementation of porous pavement. Mason currently has more than 1 acre of pervious pavement in Fairfax campus.  Permeable pavement is mainly used in low-traffic areas such as back roads, housing facilities and bike racks. The use of pervious pavement not only reduces the runoff concentrations, but also enhances the natural process of filtration.



Rain Gardens (Bioretention):

Mason has rain gardens on both Fairfax Campus and Science and Technology Campus. Each rain garden is composed of a variety of native perennial plant species, which require minimal maintenance (wildflowers, shrubs and small trees).  Rain gardens allow the storm water to penetrate into the ground and restore the water table, while simultaneously removing pollutants.





Bio-swales (Vegetated Swales)

There are several vegetated swales which treat, convey and partially infiltrate storm water runoff at different locations of Fairfax and Science and Technology Campuses. In some cases, these swales are implemented in conjunction with other structures such as check dams, which are used to reduce flow rates of runoff and allow for infiltration, where steep slopes are present.  Such swales are vegetated with water-resistant plants. A variety of small grass swales can also be found on the west side of Fairfax Campus; these work essentially as drainage ditches, but they latently provide more infiltration and pollutant removal. All George Mason University’s existing swales are used mostly as pre-treatment for other existing SWM/BMP facilities.

Detention Ponds:

Detention Ponds

Detention (dry) ponds are basins in which outlets have been designed to reduce discharge rates or in some cases, to detain stormwater for a set time to allow particles and associated pollutants to settle out. Detention ponds provide water quantity control. Extended and Enhanced Extended Detention Ponds provide water quality control in addition to water quantity control.

Mason has several detention ponds including Krasnow Pond, Braddock Pond and Roanoke Pond.



Retention Ponds

Retention (wet) Ponds are ponds that have a permanent pool of water throughout the year. These ponds treat incoming stormwater runoff by allowing particles to settle and allow biological uptake and microbial activity to take up nutrients.

Mason Pond and Prince William Pond are retention ponds.

Proprietary/Manufactured BMPs

Mason has various manufactured BMPs, such as jellyfish and CDS units. They are used to meet the water quality control requirement, where space for surface facilities is not available. They like inconspicuous manholes; however underneath is a single or series of vaults and chambers designed to remove common stormwater.

MCM6: Pollution Prevention and Good Housekeeping

The operations and maintenance program at Mason has a training component focusing on preventing and reducing the amount of pollutants in receiving waterbodies. Regular construction site inspections, infrastructure examination as well as environmental compliance assessments are key elements of our in-house management practices. Other implemented programs that help minimize issues associated with polluted runoff on campus include our recycling, waste material handling and storage procedures as well as the nutrient management plan.

MS4 Program Plan and Annual Reports