Should people swim or play near the ocean outfalls?

The ocean outfall at Conch Street in Nags Head is seen the afternoon of Wednesday, Nov. 5, 2025. (Photo by Lizzie Stoner)

By Lizzie Stoner, intern

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Ocean outfall pipes on the Outer Banks have been found to have high concentrations of bacterial contamination during and after storm events. 

A 2016 report prepared for the North Carolina Department of Environmental Quality (NCDEQ) Division of Water Resources found that the levels of the bacteria Enterococcus—which can cause infections in humans—and human fecal matter were above the state standard for recreational water use.

Ocean outfall pipes drain water from the land into the ocean to mitigate flooding. Not all rainwater can enter the groundwater, so it gets washed off hard surfaces—sometimes called impervious surfaces—and drained through these pipes, some of which empty into the ocean. 

The NCDEQ recommends that people swim at least 200 yards away from these drainpipes when there is stormwater coming from them. The department posts triangular yellow signs that warn beachgoers not to swim in the area due to an increased risk of developing a gastrointestinal illness or a skin infection. 

A yellow triangular sign high up in the sand dunes warns beachgoers not to swim within 200 yards of the stormwater discharge pipe that is located approximately one-tenth of a mile south of the East Gallery Row (Milepost 10.5) beach access and approximately two-tenths of a mile north of the Bonnett Street access in Nags Head. The sign is seen as it appears the afternoon of Monday, Nov. 17, 2025. (Photo by Corinne Saunders)

Some of the pipes discharge onto the sand, rather than into the water, which creates ponds that contain all the pollutants of stormwater without the dilution effects from the ocean. 

“Some parents like their children to play in these puddles or ponds because they think the children are safer away from the waves and current, but this is not a good idea,” according to a department document titled, “Stormwater Drainpipe Signs in North Carolina.”

Workers with the N.C. Department of Transportation clear sand in front of an ocean outfall pipe in Kill Devil Hills that had become nearly buried on May 23, 2024. NCDOT maintains the nine outfalls in Dare County. (Photo by Corinne Saunders)

The NCDEQ report lists nine ocean outfall locations in Dare County. Each outfall drains water from a designated area that is made up of a series of pipes and ditches, which are maintained by the N.C. Department of Transportation.

Between 2006 and 2014, researchers from the University of North Carolina at Chapel Hill, Coastal Studies Institute and Institute for Marine Science studied these outfall watersheds and the water quality at the nine outfalls. Their findings were published in the 2016 “Ocean Outfall Master Plan.” 

The report found that high levels of fecal indicator bacteria, such as Enterococcus and E. coli, exceeded state water quality standards. These bacteria levels were not limited to a “first flush” of storm water drainage, but persisted throughout rainfall events. 

The researchers predicted that this bacteria was due to surface septic infiltration into shallow groundwater. Watersheds—land areas that channel rainfall into creeks, streams and rivers, and eventually to outflow points like the ocean—are part of a natural filtration and treatment process. 

Development on the Outer Banks has decreased the area of natural watersheds and replaced them with impervious surfaces. Stormwater that is drained directly from impervious surfaces into the ocean carries pollutants from streets, parking lots, roofs and more. 

Researchers found that during dry periods at the testing sites, “95-98% of the time, water quality conditions are excellent.”

The ocean outfall at Curlew Street in Nags Head is seen as it appears the afternoon of Wednesday, Nov. 5, 2025. (Photo by Lizzie Stoner)

The state continues to test water quality near the ocean outfall pipes, as well as other high-traffic areas. There are 41 locations in Dare County that the NCDEQ tests. According to its website, 38 of these locations are considered daily use areas and are tested weekly during the swimming season (April 1 through Oct. 30), while the other three are tested twice a month. 

Another source of ocean outfall comes from reverse osmosis treatment plants. Reverse osmosis is the process by which water is locally treated and distributed for drinking. 

“We use membrane technology to pull the salt and everything else out of the water, and then we treat it, and then it goes into the distribution system and to the customers,” Dare County Public Utility Director Jessica King said.

Dare County has five water treatment plants and one wastewater treatment plant, according to King. Each plant is tested for water quality and contaminants every one to nine years, depending on the contaminant being tested.

At the beach access at East Oregon Avenue in Kill Devil Hills, there is a structure marked, “Danger: Deep hole, keep out” in all capital letters.

The structure with posted warnings at East Oregon Avenue in Kill Devil Hills is the outfall source for the reverse osmosis treatment plant in Kill Devil Hills. The structure is seen as it appears from the side (above) and facing the ocean (below) on Wednesday, Nov. 5, 2025. (Photos by Lizzie Stoner)

This “deep hole” is the outfall source for the reverse osmosis treatment plant in Kill Devil Hills. The discharged water from reverse osmosis plants has high salinity, residual treatment chemicals and other constituents. It has not been found to have a direct negative impact on human health. 

Outfall pipes can also have the potential to cause rip currents. Rip currents are commonly found near jetties, groins and piers—things that stick out into the ocean and obstruct the natural flow of water, according to the National Oceanic and Atmospheric Administration. Some drain pipes obstruct the water in a similar way.

The report recommended that the county improve stormwater infrastructure inventories, study shallow groundwater delivery of bacteria, enhance public education and increase warning signage. The main recommendation from the researchers and the state is not to swim near outfall pipes after rainfall. 

The ocean outfall pipe located approximately one-tenth of a mile south of the East Gallery Row (Milepost 10.5) beach access and approximately two-tenths of a mile north of the Bonnett Street access in Nags Head is seen as it appears the afternoon of Monday, Nov. 17, 2025. (Photo by Corinne Saunders)

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