It can be as simple as a public education campaign or as sophisticated as DNA testing. Cities and towns have an array of strategies to fight and prevent water pollution.
Unfortunately, more than 1,150 waterways in South Carolina are considered "impaired," too polluted to meet water quality standards, according to Carolina Clear, a Clemson Extension program that provides stormwater education and outreach.
Know the types — point and nonpoint
Point source pollution comes from a single source, such as an industrial or wastewater discharge pipe. Nonpoint source pollution, such as stormwater runoff, originates from countless places, and is one of the greatest threats to water quality in the U.S.
With stormwater runoff, rainwater gathers litter, pet waste and leaves, and washes it off roads, parking lots or rooftops directly into a storm drain that discharges into a waterway. The over-application of fertilizers and herbicides from agricultural lands or residential areas also contributes to the problem.
Other sources include spills or the dumping of oil, antifreeze or household chemicals into drainage systems. Sediment from improperly managed construction sites also pollute.
Stormwater is regulated through the S.C. Department of Health and Environmental Control, which requires many industrial sites, all construction sites of 1 acre or more, and all regulated Municipal Separate Storm Sewer Systems to have a stormwater permit.
The first step: public education
The primary sources of pollution encountered in the City of Anderson result from nonpoint urban stormwater runoff, said Billy Bolger, stormwater engineer.
Anderson officials start where the pollutant was discovered and work upstream to determine the source. This can involve addressing the issue with the party responsible for the pollution. Bolger and his staff also take steps to educate the responsible party on the harmful effects that pollutants have on waterways.
Some residents believe there is no difference between a sewer manhole and a storm drain manhole, assuming water all goes to the same place and is treated. Teaching the public about the difference helps keep waterways clean, Bolger said.
"We hope that people will have a better awareness of stormwater issues and change their behaviors to look at water as a resource needing protection," Bolger said.
The city has partnered with the Carolina Clear program and the Anderson and Pickens Counties' Stormwater Partners consortium.
"We believe this regional approach to stormwater education and resident involvement is the most effective method for providing a consistent water quality message across the upstate," Bolger said.
Along the coast, saltwater is closely monitored for bacteria, such as enterococci, that could be a risk to public health, said Andy Fairey, chief operating officer of the Charleston Water System. Bacteria can be found in stormwater from animal waste, ranging from pets to wild birds to the horses that pull carriages in downtown Charleston. DHEC monitors beaches and shellfish beds, especially after heavy rains or hurricanes, and posts warnings about high bacteria counts.
The water in Shem Creek has had high bacteria numbers in the past, leading to concerns about public recreation. But it's difficult to know what's causing it. Septic tanks seem like a likely culprit: They're permitted by DHEC, but they are privately owned and maintained. Cities and towns do not regulate them.
"That is one of the challenges that a lot of communities face," said Hillary Repik, stormwater manager for the Town of Mount Pleasant. "There's nobody who's responsible for making sure owners are actually maintaining them and doing what they're supposed to, which makes them a potential source of pollution."
And there are lots of them.
More than 1 million households in South Carolina rely on septic tanks. In an average year, 10 to 30 percent of those septic systems fail, usually because of poor maintenance. Leaky, clogged or damaged systems can contaminate a home's drinking water well; force untreated sewage to the surface of a yard and into ditches and creeks; and create sewage backups in sinks, tubs and toilets. Faulty septic tanks can also pollute nearby ponds, lakes and rivers, exposing people and animals to viruses and infections.
When rural areas are incorporated into existing sewer systems, residents often resist tying into the system because they don't want to pay monthly fees, Fairey said. Offering reasonable fees and educational outreach can help, he said.
The Town of Mount Pleasant is trying something new — DNA technology to answer a crucial question: Whose bacteria is to blame?
The bacteria samples fall into broad categories, such as human, dogs and other producers. The town is doing some small pilot testing of this process now and plans to use it more in the future with a total maximum daily load regulatory plan and other operations where it's difficult to locate a specific source.
If a sample was identified as human waste, the town would know to look at septic tanks, illegal dumping, illegal connections or sanitary sewer overflows. The DNA sample wouldn't indicate whether the bacteria came from a septic tank or an illegally emptied toilet from a recreational vehicle, but it would inform officials about what responses are appropriate.
The idea is to use the DNA to help narrow down the potential sources and figure out if the issue is a "personal pollutant," which can be reduced through education and other efforts, or whether the source is wildlife waste, which the town cannot control.
"This is a long-term process for us," said Repik. "We want to make really good decisions and get good information along the way, especially when spending taxpayer dollars, so you're doing something that will fix something and make a change — not just checking a box."
Maintaining detention ponds
Another key piece of controlling water pollution is to stop pollutants that collect in stormwater from entering the environment. If detention ponds are designed and maintained properly, they can be effective. Any developer that puts in a new development — be it housing, a mall or a parking lot — is required by state law to have a plan for stormwater.
In many cases, the developer of a residential community has an agreement with a city for the maintenance of the pond, which the developer then transfers to the homeowner association, said Kinsey Holton, stormwater program manager for the City of Charleston.
"It establishes expectations up front of what needs to be done, and that there's legal recourse if you don't maintain them," said Holton.
The ponds are not intended to stay full, but instead allow rainwater to evaporate and seep into the earth and then empty into an adjacent water body. "Inherent with a detention pond, most of the stuff — the pollutants — will somewhat settle out, but not all of it will," Holton said.
Without proper upkeep, the ponds accumulate debris, such as trash, silt and dirt. The debris builds up over time and must be removed to prevent overgrowth of green algae and bacteria, which hinders the water absorption process.
Often, the homeowner associations that assume responsibility for the ponds don't have the technical expertise to maintain them or the ability to pay for dredging every 10 to 20 years. Depending on what an analysis of the dredged material reveals, that material is sometimes hauled to a landfill or spread over land.
Another concern is residents' overuse of lawn and garden fertilizer, which collects in runoff and ends up in retention ponds.
"There is a push to make people understand, 'Hey you've got this pond in your neighborhood — Do you know you're responsible?'" said Holton.
"The average person doesn't really realize what their part is."