Heavy rainfall in May exacerbated a persistent problem in Chapin: the tendency for the town’s sewer pipes to overflow.
The town of Chapin suffered two sanitary sewer overflows this month, one on May 12 and another just days later on May 16, the S.C. Department of Environmental Services said. Both overflows caused sewage to enter Lake Murray, just yards away from a pump station. The town posted required community notices about the overflows both times.
Records from the environmental agency show that both overflows occurred in the same area, near Murray Lindler Road and Old Bush River Road, where Crooked Creek empties into an inlet of the lake. One incident led to 30,000 gallons overflowing in an eight-hour period, the agency notes. The other caused 90,000 gallons to overflow in about five hours.
The first instance was attributed to heavy rainfall, while the other was caused by a broken bypass pump that required the town to close the main valve.
“The utility properly notified [DES] of both overflows and took appropriate and immediate actions to stop both overflows, including the use of vacuum trucks,” an agency spokesperson said in an email.
Chapin attributed the May 12 leak to 2.7 inches of rain falling in a six-hour period. The problem was exacerbated by damage done to the Old Bush River pump station when a car hit it several months ago. The town has purchased a new pump, but rain has hampered efforts to install it.
“The station was hit by a vehicle which damaged our permanently mounted back up pump and piping,” Town Administrator Nicholle Burroughs said in an email. “Under normal conditions, the station runs with three pumps to ensure reliable service, but following an auto-related incident, only two pumps are currently in operation.”
Testing revealed that the overflow was “highly diluted” and consisted primarily of rainwater. The spill site was also sampled and laboratory results showed bacteria levels were within normal lake levels.
Sewer overflows have been an ongoing problem for Chapin’s town water system, which serves around 7,000 households north of Lake Murray. In 2022 and again in 2023, rainfall led to around 2,000 gallons of runoff near the lake.
“In the past, this wastewater collection system has had inflow and infiltration issues, especially after significant rain events,” the Department of Environmental Services said. “The Town has made adjustments to the collection system to help mitigate these overflows, and SCDES staff are in contact with the system about additional steps to address the issues.”
“A lift station that leaks 120,000 gallons of sewage water in two separate spills within several days into a small cove of the lake is a concern,” said Charli Wessinger, who represents the area on Lexington County Council. “I’ve heard from many constituents in the unincorporated areas around Chapin of sewer smells and leaks from multiple sewer pump and lift stations. I’ve reached out to SCDES to help with this situation as it has become a potential health concern for the environment and the lake.”
The town posted to Facebook to blame the sewer overflows on heavy rainfall, saying it is a common cause of overflows.
“Sewer systems are not designed or intended to transport or treat rainwater,” the Facebook post reads. “The sewer collection system will handle the additional flow for a while, but eventually it gets to maximum capacity and then overflows at the lowest opening in the area. Many times, this is at our pump stations.”
Besides the environmental impact, overflows can increase costs on town residents and water customers. The town said sewer overflows double the water department’s electrical, chemical and contractor costs. Outside contractors have to come in to clean up spills and transport waste to the town’s wastewater treatment plant.
“We, more than anybody want to prevent these overflows and have been working diligently for years now to identify the causes and resolve them,” such as adding a $1.6 million surge basin at the wastewater plant to hold excess flows, and upgrading pump stations and main lines to handle higher flows, the town said. “We are currently spending in excess of $4.5 million to install the largest size sewer main in Chapin’s history, to relieve the higher pressures in the sewer mains that slow the flow to the WWTP.” That project is expected to be completed by the end of the year.
But the true solution to the problem, the town says, is keeping rainwater out of the sewer system in the first place.
Chapin has conducted “smoke tests” around town to identify where rainwater might be entering the system. The town blows smoke into pipes and looks for areas where the smoke escapes as possible entry points. Photos posted by Chapin of a street where a smoke test was being performed showed plumes of white smoke shooting out of cracks in sidewalks, residents’ lawns and even the gutters of a home.
“The smoke tests have shown us so far that 98% of these identified sources are on the homeowners’ pipes not the utility’s mains,” the town’s statement said. These house pipes are the responsibility of the homeowner to maintain.
“We are sure there will be a few sources that are on utility-owned mains, but it is far more likely the majority of these rainwater intrusions are coming from the pipes within the yards of the approximately 7,000 sewer customers currently tied into our system.”
At its May 20 meeting, Chapin Town Council approved the next phase of a planned expansion of the town’s wastewater treatment plant. The town approved a $1.04 million contract with AECOM Engineering to upgrade the plant’s main line as well as engineering work on the plant itself. The upgrade is actually required because the utility is projected to reach 80% of its current plant capacity in as little as 10 years, or sooner if a new industrial project locates in the area.
“The engineering and expansion of the wastewater treatment plant is not a response to recent rain-related events, but rather a proactive measure to responsibly plan for future demands,” Burroughs said. “This initiative reflects the Town’s commitment to staying ahead of growth and ensuring our infrastructure is prepared to support continued development in a sustainable and efficient manner.
“To this end, the recent implementation of impact fees ensures that developers contribute an equitable share of the costs associated with any new development,” she added, pointing to fees paid by developers bringing new projects to the area. “These fees help offset the strain placed on our infrastructure, particularly from projects originating outside our jurisdictional boundaries.”