Nevada Department of Transportation
Home MenuMunicipal Separate Storm Sewer Systems (MS4) Permit
What is an MS4?
An MS4 is a conveyance or system of conveyances that is:
- Owned by a state, city, town, village or other public entity that discharges to waters of the U.S.;
- Designed or used to collect or convey stormwater (including storm drains, pipes, ditches, etc.);
- Not a combined sewer; and
- Not part of a Publicly Owned Treatment Works (sewage treatment plant).
Stormwater runoff conveyed through an MS4 is often polluted and discharged untreated into local waterways. Consequently, many MS4 operators must obtain coverage under an MS4 Permit issued under the Clean Water Act's National Pollutant Discharge Elimination System and thereby develop and implement a stormwater management program (SWMP) to reduce potential stormwater pollution and prohibit illicit discharges.
National Pollutant Discharge Elimination System (NPDES)
Phase I, issued in 1990, requires medium and large cities or certain counties with populations of 100,000 or more to obtain NPDES permit coverage for their stormwater discharges. Phase II, issued in 1999, requires regulated small MS4s in urbanized areas, as well as small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges. Generally, Phase I MS4s are covered by individual permits, and Phase II MS4s are covered by a general permit.
During Phase I, NDOT was defined as the co-permittee on large MS4 Permits for Clark and Washoe counties. In the wake of Phase II, NDOT was faced with co-permittee responsibilities for all regulated small MS4 areas, as well as the individual permit for the Lake Tahoe basin. NDOT requested a single statewide NPDES permit from the Nevada Division of Environmental Protection (NDEP) to fulfill the large and small MS4 requirements, as well as the Lake Tahoe permit. In February 2004, NDOT was issued the NPDES MS4 Permit NV0023329 by NDEP. In September 2004, NDOT received a letter from NDEP confirming acceptance of NDOT’s request to cancel the discharge permit NV0023205 for NDOT discharges within the Lake Tahoe basin. NDEP reissued MS4 Permit NV0023329 to NDOT in 2010 and 2018.
NDOT’s MS4 Permit covers “state and interstate highways and their right-of-ways within the jurisdictional boundary of the Nevada Department of Transportation (“NDOT” or “Permittee”) served by, or otherwise contributing to discharges into receiving Waters of the United States from municipal separate storm sewer systems (“MS4s”) owned or operated by NDOT.”
NDOT has developed a SWMP Plan to comply with MS4 Permit requirements and address stormwater pollution related to its highway planning, design, construction and maintenance activities throughout the state. Included with the SWMP Plan is a copy of NDOT's MS4 Permit. The SWMP Plan is available for download in the Resources/Documents section.
NDOT's Environmental Division administers the implementation of the SWMP, including reporting. Each year, NDOT is required to report the status of the SWMP, including any modifications, and the plans for implementing those modifications. Annual Reporting is due November 1 of each year and covers the previous fiscal year's activity.
Free viewers are required for some of the attached documents.
They can be downloaded by clicking on the icons below.
