Is Charleston, SC tap water safe?
Supplied by Charleston Water System · serves 278,771 people (126,756 connections) · Surface water · EPA ID SC1010001
Data: U.S. EPA · How we read the data · How we check it
Summary
PFAS above the 2024 federal limits. Systems have until 2029 to meet the PFAS limits.
Is it an emergency? No: PFAS limits are about years of exposure, not a glass of water, and nothing in EPA's data calls for you to stop drinking the water today. If your utility ever issues a boil-water or do-not-drink notice, follow it.
- PFAS
- Above limitPFOA, PFOS above the federal limit in EPA's 2023–2025 testing (PFOA 4.33 ppt vs a limit of 4 ppt, PFOS 5.83 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lead
- Below action level3.5 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period ending Dec 2024. Your home's pipes can make yours higher.
- Violations
- Resolved2 health-based violations since 2016, most recently Jul 2025.
- Pregnant, or mixing baby formula with tap water? Babies drink more water for their size, so PFAS exposure matters more for them. Consider bottled water or a filter certified for PFAS for formula, and ask your doctor. Health effects.
- To lower your PFAS exposure now, a home filter certified for PFAS reduction works (reverse osmosis, or activated carbon certified to NSF/ANSI 53 or 58). Filters for these results.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Charleston Water System's 2026 water quality report (Consumer Confidence Report, from the utility). It lists every regulated contaminant tested, including ones not on this page. Questions: (843) 863-4038.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Mar 2025 to Dec 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Above limit Limit 4 ppt | 4.33 ppt 1.08× the limit |
| PFOS Above limit Limit 4 ppt | 5.83 ppt 1.46× the limit |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Detected, below limit Limit 1 | 0.0019 |
| PFBS Detected, below limit Guideline 2,000 ppt | 3.9 ppt |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Detected, below limit Guideline 3,000 ppt | 4.15 ppt |
| PFPeA Detected, no limit | 4.63 ppt |
For context: the PFOA average is higher than at 80% of the South Carolina systems EPA tested and the PFOS average is higher than at 75% of the South Carolina systems EPA tested.
29 PFAS tested, 5 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 4 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 3.5 ppb lead (Jan 2022 – Dec 2024). Below action level
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2022 – Dec 2024 | 3.5 ppb |
| Jan 2019 – Dec 2021 | 2.1 ppb |
| Jan 2016 – Dec 2018 | 2.3 ppb |
Earlier results (9)
| Jan 2013 – Dec 2015 | 1.3 ppb |
| Jan 2010 – Dec 2012 | 2.3 ppb |
| Jan 2007 – Dec 2009 | 4.5 ppb |
| Jan 2004 – Dec 2006 | 3 ppb |
| Jan 2003 – Dec 2003 | 4 ppb |
| Jan 1999 – Jul 1999 | 3.8 ppb |
| Jul 1998 – Jan 1999 | 4 ppb |
| Jul 1997 – Jan 1998 | 4 ppb |
| Jul 1993 – Jun 1997 | 2.2 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
| When | What happened |
|---|---|
| Jan 2025 – Jul 2025 2 times | The water chemistry that keeps lead from dissolving out of pipes was outside the range the state set. EPA record: Lead and Copper Rule · WQP Entry Point/Tap Treatment Technique Non-Compliance (limit TT ) Archived |
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 14.4 ppb | 300 ppb |
| Strontium | 0.061 ppm | 1.5 ppm |
| Chlorate | 240 ppb | 210 ppb |
| Chromium-6 | 0.079 ppb | – |
| Vanadium | 1.4 ppb | 21 ppb |
| 1,4-Dioxane | 0.24 ppb | 0.35 ppb |
Where it serves
Charleston
35 ZIP codes the system reported serving
29401, 29402, 29403, 29404, 29405, 29406, 29407, 29409, 29410, 29412, 29414, 29418, 29420, 29423, 29424, 29425, 29426, 29429, 29439, 29445, 29449, 29450, 29451, 29455, 29456, 29461, 29464, 29466, 29470, 29482, 29483, 29485, 29486, 29487, 29492
Nearby utilities
- Mt Pleasant Waterworks Mount Pleasant · 6 mi · PFAS above limit
- Dcws Ashley Phosphate Water System North Charleston · 8 mi · PFAS above limit
- City of Folly Beach Folly Beach · 11 mi · PFAS above limit
- Isle of Palms Water & Sewer Commission Isle of Palms · 13 mi · PFAS above limit
- Kiawah Island Utility Kiawah Island · 15 mi · PFAS above limit
- Dcwa Calomet Valley Water System Summerville · 17 mi · PFAS above limit
Questions
Is Charleston tap water safe to drink?
Most of Charleston gets its water from Charleston Water System. Charleston Water System had 2 health-based violations since 2016, all since resolved. EPA testing found PFAS above the 2024 federal limits, which systems must meet by 2029. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Charleston water have PFAS?
Yes. EPA's 2023–2025 testing of Charleston Water System found 5 PFAS at least once. The highest entry-point averages were above the federal limit for PFOA and PFOS: PFOA 4.33 ppt, PFOS 5.83 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Charleston water?
The most recent 90th-percentile lead result for Charleston Water System is 3.5 ppb, for the period ending Dec 2024. The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for SC1010001: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID SC1010001).
- EPA SDWIS download: the lead results, population and violation records we use.
- Charleston Water System's 2026 water quality report: the utility's own annual report, including contaminants EPA's national database doesn't carry (link checked Nov 14, 2026). Phone: (843) 863-4038.
- Charleston Water System website
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.