Statewide Compliance and Testing

• Overall Compliance: The majority of South Carolina’s 650+ public water systems meet federal Safe Drinking Water Act standards. However, SCDES testing of all public water systems between 2020 and 2023 found more than 100 with high PFAS levels — a significant proportion of the state’s supply base. The PFAS systems list was last updated by SCDES in April 2024.
• PFAS Monitoring: South Carolina faces widespread PFAS exposure, with elevated concentrations identified particularly in watersheds near military installations and industrial sites. Charleston Water System, which has been voluntarily testing for dozens of PFAS compounds since 2017, recorded PFOS at 5.56 ppt — above EPA’s enforceable MCL of 4 ppt. Removing that 1.56 ppt excess is estimated to cost at least $100 million upfront with approximately $10 million annually in ongoing operational costs.
• Infrastructure Investment: South Carolina received over $11 million from the Bipartisan Infrastructure Law specifically for PFAS treatment. Broader drinking water infrastructure funding has also been allocated through the State Revolving Fund programme, though the American Society of Civil Engineers projects a funding gap of approximately $6 billion over the next 20 years for the state’s water needs.

Major Water Sources and Challenges

• Ashley River Basin: Serves the Charleston metropolitan area but faces severe PFAS contamination from Joint Base Charleston, where groundwater testing has revealed levels of approximately 1.15 million ppt — among the highest ever recorded nationally. Military use of AFFF (aqueous film-forming foam) for firefighting training has contaminated surrounding watersheds.
• Coastal Water Systems: Charleston Water System serves over half a million South Carolinians and has proactively monitored PFAS since 2017, conducting 80+ voluntary tests. Current PFOS levels of 5.56 ppt exceed the 4 ppt MCL. The utility has confirmed it will comply with the federal standard and is planning treatment upgrades.
• Statewide Infrastructure Needs: EPA projects over $4.5 billion needed for replacing ageing distribution and transmission pipelines alone, with particular challenges in rural areas lacking adequate funding and technical capacity. For broader context, see our water quality checker.

Emerging Contaminant Response

• PFAS Regulation Update (2025–2026): On May 14, 2025, EPA announced its intent to revise the PFAS National Primary Drinking Water Rule — retaining the PFOA and PFOS MCLs at 4 ppt but extending the compliance deadline from 2029 to 2031, and proposing to rescind MCLs for PFHxS, PFNA, HFPO-DA (GenX), and the Hazard Index mixture. SCDES states it is closely monitoring this process. Initial monitoring by all water systems is required by April 2027.
• Treatment Technology Deployment: Water utilities are implementing advanced treatment technologies including granular activated carbon filtration and reverse osmosis systems to remove PFAS and other emerging contaminants. Charleston Water System is actively planning treatment upgrades and has confirmed it will comply with the federal standard regardless of regulatory timelines.
• No State PFAS Regulations: South Carolina does not have any state-level PFAS drinking water regulations. This means residents rely entirely on federal standards and voluntary utility monitoring. SCDES continues to publish PFAS testing data and provide private well testing assistance. See our boil water tracker for current SC advisories.

Rural and Disadvantaged Communities

• Infrastructure Disparities: Rural water systems face disproportionate challenges with ageing infrastructure, limited technical capacity, and higher per-capita costs for compliance with new regulations, particularly affecting communities in Tier III and IV counties across the state.
• State Infrastructure Support: The South Carolina Rural Infrastructure Authority has awarded grants under the SC Infrastructure Investment Program targeting water, sewer, and stormwater improvements for smaller and rural communities, with dedicated funding streams providing grants and forgivable loans.
• Private Well Testing: SCDES offers free PFAS assessment for private drinking water well owners through the Individual Private Well PFAS Assessment Application programme. Priority is given based on aquifer vulnerability, well susceptibility, and proximity to known PFAS sources. Well owners found to have PFAS may be eligible for filtration installation or connection to public supply at no cost.

Looking Forward: 2026–2031

South Carolina’s water quality landscape faces significant change as the PFOA/PFOS compliance deadline of 2031 approaches. With more than 100 public water systems recorded as having elevated PFAS levels, and no state-level PFAS regulations in place, residents depend on federal standards and utility-level action. The state’s lack of its own PFAS rules means that the ongoing uncertainty around federal regulation — following EPA’s May 2025 announcement — has a more direct impact here than in states with independent standards. Charleston Water System’s proactive voluntary monitoring and planned treatment upgrades represent a model for the state, but many smaller utilities face significant cost pressures. Successful outcomes will require sustained collaboration between SCDES, water utilities, federal agencies, and communities to ensure all South Carolinians have access to safe, affordable drinking water. For filter solutions appropriate to South Carolina’s contamination profile, see our recommended water filters.