Stormwater Management

What is Stormwater?

Stormwater runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces. The runoff is the water that does not percolate into the ground or is not otherwise stored. As the runoff flows over the land or impervious surfaces (paved streets, parking lots, and building rooftops), it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff is discharged untreated. The primary method to control stormwater discharges is the use of best management practices (BMPs). In addition, most stormwater discharges are considered point sources and require coverage under an NPDES permit.

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What is the Npdes Stormwater Program?

The National Pollutant Discharge Elimination System (NPDES) Stormwater Program regulates stormwater discharges from three potential sources: municipal separate storm sewer systems (MS4s), construction activities, and industrial activities. Most stormwater discharges are considered point sources, and operators of these sources may be required to receive an NPDES permit before they can discharge to State waters and open bodies of water. This permitting mechanism is designed to prevent stormwater runoff from washing harmful pollutants into local surface waters such as streams, rivers, lakes or coastal waters.

In October 2000, EPA authorized the Florida Department of Environmental Protection (DEP) to implement the NPDES stormwater permitting program ( in the State of Florida (in all areas except Indian Country lands). FDEP's authority to administer the NPDES program is set forth in Section 403.0885, Florida Statutes (F.S.). The NPDES stormwater program regulates point source discharges of stormwater into surface waters of the State of Florida from County, Municipal, industrial and construction activities. As the NPDES stormwater permitting authority, FDEP is responsible for promulgating rules and issuing permits, managing and reviewing permit applications, and performing compliance and enforcement activities.

What Are the City'S Stormwater Requirements?

Under the FDEP stormwater program, the City of Mary Esther has been granted a MS4 permit to convey and discharge stormwater to the Santa Rosa Sound. Stormwater from the upland areas in Okaloosa County and Fort Walton Beach is conveyed to the City of Mary Esther and ultimately ends up in the Santa Rosa Sound. Because the Santa Rosa Sound is the receiving body of water, there are strict requirements for the discharge of stormwater from residential and commercial properties. The City has an adopted ordinance titled illicit discharge which can be found in Article 11.07.00 in the City’s Land Development Code. This ordinance governs all stormwater discharges within the City limits and has specific requirements for discharges, prohibitions of certain activities, construction site monitoring, post construction controls and best management practices.

For new construction, the adopted Level of Service for drainage is to retain the first inch of run-off on-site; and post-development run-off shall not exceed pre-development runoff rate for a 25-year storm event, up to and including an event with a 24-hour duration. This helps with keeping the stormwater on site and reduces the risks of flooding. It also helps to recharge our aquifer and cuts down of point and non-point source pollution.

Illicit Discharge Elimination Program (IDEP)

By definition, an illicit discharge is any discharge to a municipal separate stormwater sewer system that is not composed entirely of stormwater. Discharge of chemicals, sediment, trash, chlorinated swimming pool water, etc. into the stormwater system are direct violations of the illicit discharge ordinance whether the discharge was intentional or not. Fines for violation of the City’s stormwater ordinance can range up to $5,000.00 for irreparable offenses. Having knowledge of and failing to report an illicit discharge can also land you in hot water as you are required to immediately take action to abate the discharge and notify the City within 24 hours and provide a written report within 72 hours.

As part of the City’s Illicit Discharge Elimination Program, City employees are trained and educated to identify illicit connections and discharges to the stormwater drainage system. The most common warning signs of illicit discharges are dry weather flow, suds, sewage, oil and gas. Employees regularly conduct inspections of the stormwater system, construction sites, businesses and residential homes to verify compliance with the NPDES and IDEP.

There are two types of illicit discharge contributors. Point source discharges (PSD) and non-point source discharges (NPSD). A PSD is characterized as a single identifiable source such as a commercial dumpster leaching chemicals or a discharge pipe releasing waste.  A non-point source discharge (NPSD) is a source of pollution that washes from roofs, streets, yards, driveway, sidewalks, and other land areas into water bodies.

Program Goals & Objectives


To eliminate discharges introduced into the City’s lake, streams, ponds, sound, and waterways that make up the stormwater infrastructure that are harmful to both people and the environment by public outreach, ordinance enforcement, and best management practices.

Program Focus

The program focuses on the elimination of improper connections to the storm water system, elimination of illegal dumping into storm sewers, illicit discharges, environmental hazards, procedures, inspections, reports, warning signs, and minimizing the amount of seepage into the storm water system from the sanitary sewer system and septic systems.


  • Illicit Discharge: Any discharge (or seepage) to the separate storm water drainage system that is not composed entirely of storm water or uncontaminated groundwater.
  • Illicit Connection: A physical connection to a separate storm water drainage system that primarily conveys illicit discharges into the system and/or is not authorized or permitted by the local authority.
  • Point Source Discharge Pollution: Pollution from a single identifiable source.
  • Non-Point Source Discharge Pollution: Pollution that washes from roofs, streets, yards, driveways, sidewalks, and other land areas into water bodies.
  • Pollution: Contamination of the air, water, or soil by the addition of harmful substances.


Inspections are performed on a regular basis in a manner approved by the Department. The Maintenance Department conducts regular inspections of the stormwater system when checking ditches, ponds, drains and grates for debris. Any findings that may be a violation are reported to the Code Enforcement, Planning and Zoning Department.
The Code Enforcement, Planning and Zoning Department conduct both pro-active and re-active inspections of stormwater discharges and specifically look for possible violations. Inspections take place during rain events and dry weather events.


Illicit discharges are generally any discharge into a storm drain system this is not composed entirely of stormwater. The exceptions include water from firefighting activities, de-chlorinated swimming pool discharges and discharges from facilities already under an NPDES permit. Illicit discharges are a problem because unlike wastewater which flows to a wastewater treatment plant, stormwater generally flows to waterways without any additional treatment. Illicit discharges often include pathogens, nutrients, surfactants, and various toxic pollutants.

Oil & Gas

Oil and gas can travel a long way from its original source. It is often seen as sheen on the water. If the sheen is stirred and separated and it reattaches, it is most likely oil or gas. Oil and gas, when dispersed into the environment, is very harmful to the waterways and all life forms within those waterways. Whenever oil or gas is suspected to be in the waterway, a spill kit should be used to contain the contaminants and remove them from the area of pollution.
Oil/Gas is recognized as sheen on the water. Natural sheens may be differentiated from oil/gas sheens by swirling the sheen around in the water. If it re-attaches, the sheen is oil or gas. Natural sheens will remain separated. Oil and Gas enters water bodies via storm water runoff from spills and illegal dumping.

Grass & Other Vegetation

Grass and other vegetation is often overlooked. Vegetation is very rich in nutrients which can cause an increase in algae growth within the body of water of which it is located. Nutrient input can reduce dissolved oxygen levels within a water system which is necessary for biodiversity. When vegetation, grass, leaves, etc. is dumped into the stormwater system, it can cause blockages of the stormwater flow, can kill other vegetation and lead to stability and erosion problems of streams, banks, hills, etc., and can cause fish kills from reduced available oxygen. Grass and leaves should never be blown into a storm drain or into the roadway.

Suds & Detergents

Suds and detergents are specifically harmful to fish because suds deplete oxygen levels in the water. Suds can enter any water system where there is a flow of water. This is often a problem when cars are washed on an impervious surface instead of on the lawn where the water can be absorbed or when wash machine discharge pipes are piped to a ditch or body of water.

Sanitary Sewage

Sanitary sewage may be present if there is black staining inside the drainage pipe. Visible evidence of sanitary waste may be raw sewage, toilet paper or opaque and gray water. Sewage may originate from septic tank overflow pipes, main line brakes, illicit connections or illegal dumping and discharging.

Dry Weather Flow

Dry weather flow is when it has not rained for at least 72 hours and the storm drain has flow or the drain shows signs of intermittent flow, staining or odor. This is the result of an illegal discharge or unaccounted water loss.

Other examples of hazards and illicit discharges are:

  • Over-fertilization
  • Swimming Pool Backwashing and Water Discharging that is not dechlorinated
  • Dumping chemicals directly into the storm drain
  • Track out and sediment discharge