Septic Tanks: A Hidden Menace
Septic tanks are a hot topic in Charleston and other coastal communities because they pollute nearby creeks, rivers, and bays, especially in low lying areas experiencing the impacts of climate change. In our community, many local waterways often show unsafe levels of fecal bacteria from septic tanks, posing serious environmental and public health risks.
Local artist and clean water activist Mary Edna Fraser used to swim daily off her dock on James Island Creek. However, after repeatedly falling ill from contaminated water, she stopped. DNA tests confirmed that human waste from septic tanks is one of the leading causes of this fecal contamination in James Island Creek.
The South Carolina Department of Environmental Services (DES) currently doesn’t track the number of septic systems in the state. However, others estimate that 40% of South Carolina residents rely on septic systems, and about one-third of new developments are installing them. Despite this widespread use, surveys indicate that many people know little about how their septic systems work.
What is a septic system?
A septic system uses a holding tank and a drain field to treat sewage and wastewater from homes and businesses that are not connected to public sewer. The process works by allowing wastewater to pass into the drainfield and then through the soil, filtering out bacteria and contaminants before they reach groundwater or flow into nearby creeks and rivers.
A key factor in this process is the separation distance—the space between the drainfield and groundwater. This distance should be large enough to give the wastewater enough time to filter through the soil before it reaches groundwater or surface water.
However, problems arise when this separation distance is too small or compromised. This can happen due to rising groundwater levels (also known as the water table), sea level rise, floods, and heavy rains. When the water table gets too high, untreated wastewater containing fecal bacteria and other pathogens can flow into our waterways.
Water tables can fluctuate due to seasonal rainfall or changes in tides and sea levels, especially in coastal areas. In regions like Charleston, which experience frequent flooding, high water tables, and water-logged soils, septic systems are particularly prone to failure. James Island Creek is a prime example of this problem. It is a critically impaired waterbody, where bacteria levels often exceed safe limits, especially after rainstorms.
While South Carolina’s Department of Environmental Services requires inspection and permitting before septic tanks are installed, many systems still fail shortly after installation. Current regulations and permitting requirements are inadequate to fully protect public health and water quality.
Weak Regulations
SCDES regulations include requirements for separation distance, setback distance (distance from critical areas like marshes and waterways), and soil type. However, these regulations fail to prevent untreated wastewater and bacteria from contaminating local waterways especially in low lying coastal areas.
For instance, SC Reg 61-56 only requires a six-inch separation distance, leaving minimal room for wastewater to filter through the soil before reaching groundwater. In contrast, North Carolina generally requires a greater separation distance which is determined based on factors such as soil type. South Carolina’s septic regulations also lack a minimum lot size requirement, meaning they do not account for the density of septic systems in an area. Too many septic systems close together can overwhelm the soil, leading to system failures, especially during high tides or heavy rains.
Local Conditions and Climate Impacts
Current regulations also fail to account for rainfall patterns, flood frequency, climate change, and sea level rise, all of which impact the ability of a septic system to properly treat sewage. Additionally, SCDES lacks any effective mechanism to determine how many septic tanks are in use in South Carolina, what condition they are in, and whether or not they are polluting nearby waterways.
South Carolina’s soil types are diverse, but many are poorly draining with high water tables, especially in the Lowcountry. All of that makes flooding, malfunctioning septic systems, and water pollution more likely. As development pressures grow and more septic systems are installed in low lying flood prone areas, fecal contamination in local waterways will only become more common. South Carolina’s septic tank regulations must be upgraded to better suit the local conditions and a changing climate.
Action for Clean Water
Coastal Zone Consistency Review
Charleston Waterkeeper and the Coastal Conservation League, represented by the South Carolina Environmental Law Project (SCELP), sued SCDES demanding that septic tank permits in coastal areas be reviewed under the state’s Coastal Zone Management Act and to require public notice for all permit applications. This would give SCDES a more robust set of tools for septic tank permitting decisions in coastal areas. The case is still pending in state court.
James Island and Shem Creek
Working with local communities and elected leaders, Charleston Waterkeeper advocated for funding to support sewer upgrades for James Island and Shem Creek. Mount Pleasant Waterworks was awarded grant money to extend sewer lines and transition homeowners from septic to sewer where possible.
With the support of local elected leaders, The James Island Public Service District also won funding and received two consecutive allocations in the state budget for residents near James Island Creek to connect to sewer lines.
Greenville County
In the Upstate, Greenville County took a bold approach to preventing septic tank pollution. In early 2024 Council approved a new ordinance requiring a minimum lot size for septic permits of 1.5 acres for projects with 10 or more lots and to redirect growth to areas with access to water and sewer. The ordinance also mandates a 50-foot vegetative buffer between new structures and waterways, with increased setback distances in some cases. These new rules are a strong example for what can be done by local governments in the coastal zone.
What YOU can do:
We don’t have to accept septic tank pollution and degraded waterways are part of living in the Lowcountry, we have the power to drive change and force local leaders to become stronger stewards of clean water for future generations. Take action for clean water today:
Talk to your state and local elected officials about septic tanks and bacteria pollution. Ask them to support action that (1) funds water and sewer upgrades, (2) improves state regulations, especially vertical separation distance and minimum lot size requirements, and (3) requires SCDES to use the state’s coastal zone rules for permitting decisions in coastal counties.
If you have a septic tank, have it inspected by a professional, regularly maintained, and pumped out to ensure it is working properly.
Want to learn more? Read this…
References
§ 51.134 CONNECTION TO THE WASTEWATER SYSTEM WHEN AVAILABLE., (2011). https://codelibrary.amlegal.com/codes/mtpleasantsc/latest/mpleasant_sc/0-0-0-114086
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