Drinking water quality · 2024
What's in Charleston, SC tap water
46 contaminants were measured in the Charleston, SC water system's 2024 annual report. Each is shown below against its federal limit — 2 sit at or above that limit.
- Reporting year
- 2024
- Contaminants measured
- 46
- Over federal limit
- 2
- Approaching the limit
- 0
- Worst contaminant
- PFOS
- Service area
- SC
PFAS — EPA UCMR5 (2023–2025)
2 PFAS compounds above EPA limits in Charleston, SC
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (1.6×)PFOA (Perfluorooctanoic acid)
● Over EPA limit (1.1×)PFHxA
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFBS
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Charleston, SC's drinking water comes from surface water, drawn from 2 sources.
Source
- BUSHY PARK RESERVOIR
- EDISTO RIVER
Treatment
- HANAHAN WATER TREATMENT (A10001)
Distribution
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based5 violations on record · most recent Jul 1984resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChloramineA longer-lasting disinfectant made by combining chlorine with ammonia. | 3–3 mg/LReported levelActual Level in CWS Water for 2024 | 4 mg/LMCL | Within the limit |
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 400 ug/LReported levelActual Level in CWS Water for 2024 | None set | Within the limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 3.3 ng/LReported levelAug 2018 | None set | Within the limit |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | 2.3 ng/LReported levelJan 2024 | None set | Within the limit |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | 3.2 ng/LReported levelAug 2018 | None set | Detected — no federal limit |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | 8 ng/LReported levelOct 2020 | None set | Detected — no federal limit |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 17.28 ug/LAverageDistribution Water | None set | Within the limit |
| BromodichloromethaneA trihalomethane disinfection byproduct. | 5.6 ug/LReported levelAug 2018 | 100 ug/LNL | Detected — no federal limit |
| BromoformA trihalomethane disinfection byproduct. | 0.5 ug/LReported levelNov 2021 | 1 ug/LNL | Detected — no federal limit |
| ChloroformA trihalomethane formed when chlorine reacts with organic matter in water. | 7.2 ug/LReported levelAug 2018 | 350 ug/LNL | Detected — no federal limit |
| DibromochloromethaneA trihalomethane disinfection byproduct. | 2.6 ug/LReported levelAug 2018 | 700 ug/LNL | Detected — no federal limit |
| NDMA | 7.7 ng/LReported levelOct 2020 | None set | Detected — no federal limit |
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 0.44 ug/LReported levelFeb 2022 | 25 ug/LNL | Detected — no federal limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 0.0035 mg/L90th percentileAt the tap | 0.015 mg/LAction level | Within the limit |
| SeleniumA trace element from natural deposits and industrial discharge. | 5.4–5.4 ug/LReported levelActual Level in CWS Water for 2024 | None set | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 90 ug/LReported levelActual Level in CWS Water for 2024 | None set | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 19 ug/LReported levelOct 2023 | 7 ug/LNL | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | 94 ug/LReported levelJan 2024 | None set | Detected — no federal limit |
| BoronA naturally occurring element from rock and soil. | 37 ug/LReported levelAug 2018 | None set | Detected — no federal limit |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 0.33 ug/LReported levelOct 2020 | None set | Detected — no federal limit |
| IronA naturally occurring metal common in groundwater. | 0.11 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ManganeseA naturally occurring metal from soil and rock. | 9.38 ug/LAverageFinished Water | None set | Detected — no federal limit |
+By source (2)— Finished Water, Distribution Water
| |||
| SilicaA naturally occurring compound from sand and rock. | 8.1 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 9.5 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| Strontium | 53 ug/LReported levelAug 2018 | 20 ug/LNL | Detected — no federal limit |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | 6.3 ug/LReported levelFeb 2019 | 10 ug/LNL | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.16 mg/LReported levelActual Level in CWS Water for 2024 | 4 mg/LMCL | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 0.14 mg/LReported levelActual Level in CWS Water for 2024 | None set | Within the limit |
| BromideA naturally occurring salt found in source water. | 0.04 ug/LAverageRaw Water | None set | Detected — no federal limit |
| ChlorideA naturally occurring salt compound. | 14 mg/LAverageSystem-wide | None set | Detected — no federal limit |
VOCs & pesticides
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Cryptosporidium | 0Reported levelActual Level in CWS Water for 2024 | None set | None detected |
| Giardia lamblia | 0.1Reported levelActual Level in CWS Water for 2024 | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AlkalinityA measure of the water's capacity to neutralize acids. | 30 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ColorA measure of visible tint in the water. | 4AverageSystem-wide | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 56 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 176AverageSystem-wide | None set | Detected — no federal limit |
| TemperatureThe measured temperature of the water sample. | 71.6AverageSystem-wide | None set | Detected — no federal limit |
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 7.45 mg/LAverageRaw Water | None set | Detected — no federal limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 101 mg/LAverageSystem-wide | None set | Detected — no federal limit |
People also ask about Charleston, SC's water
+Is Charleston, SC tap water safe to drink in 2024?
The 2024 Consumer Confidence Report for the Charleston, SC water utility lists 2 contaminants at or above the federal limit: PFOS and PFOA. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Charleston, SC tap water?
46 contaminants were measured in Charleston, SC's 2024 Consumer Confidence Report, spanning metals, pfas ("forever chemicals"), and disinfection byproducts. 16 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Charleston, SC tap water?
2 contaminants in Charleston, SC's 2024 report sit at or above the federal limit: PFOS (2.4× the limit); PFOA (1.3× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Charleston, SC tap water?
The contaminant with the highest measured value relative to its federal limit in the 2024 report is PFOS, at 2.4× the federal threshold. It belongs to the pfas ("forever chemicals") family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Charleston, SC's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Charleston, SC's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.