Drinking water quality · 2024
· Verified
· PWSID SC1010001
What's in Charleston, SC tap water
2 contaminants in Charleston, SC's water sat at or above a federal limit, led by PFOS (Perfluorooctane sulfonic acid) at 1.6x the limit.
- !2 contaminants at or above a federal limit — worst is PFOS (Perfluorooctane sulfonic acid) at 1.6x
- !11 of 27 core regulated contaminants reported — 16 never appear in this report
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −34 contaminants at or above a federal limit
- −0 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −13 core regulated contaminants never reported (11/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- PFOS (Perfluorooctane sulfonic acid)1.6× the federal limit6.5 ng/L · limit 4 ng/L
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 70% of U.S. systems
- PFOA (Perfluorooctanoic acid)1.1× the federal limit4.4 ng/L · limit 4 ng/L
Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 60% of U.S. systems
+44 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| Chloramine | 3–3 mg/L | 4 mg/L |
| Perfluorohexanesulfonic acid | 3.3 ng/L | 10 ng/L |
| HAA5 | 17.28 ug/L | 60 ug/L |
| Lead | 0.0035 mg/L | 0.015 mg/L |
| Hexafluoropropylene oxide dimer acid | 2.3 ng/L | 10 ng/L |
| Selenium | 5.4–5.4 ug/L | 50 ug/L |
| Chlorine | 400 ug/L | 4000 ug/L |
| Copper | 90 ug/L | 1300 ug/L |
| Fluoride | 0.16 mg/L | 4 mg/L |
| Nitrate | 0.14 mg/L | 10 mg/L |
| Barium | 19 ug/L | 2000 ug/L |
| Atrazine | 24 ng/L | 3000 ng/L |
| Simazine | 16 ng/L | 4000 ng/L |
| Bromodichloromethane | 5.6 ug/L | 100 ug/L |
| Bromoform | 0.5 ug/L | 1 ug/L |
| Chloroform | 7.2 ug/L | 350 ug/L |
| Dibromochloromethane | 2.6 ug/L | 700 ug/L |
| NDMA | 7.7 ng/L | — |
| Perchlorate | 0.44 ug/L | 25 ug/L |
| Bromide | 0.04 ug/L | — |
| Chloride | 14 mg/L | — |
| Aluminum | 94 ug/L | — |
| Boron | 37 ug/L | — |
| Chromium, Hexavalent | 0.33 ug/L | — |
| Iron | 0.11 mg/L | — |
| Manganese | 9.38 ug/L | — |
| Silica | 8.1 mg/L | — |
| Sodium | 9.5 mg/L | — |
| Strontium | 53 ug/L | 20 ug/L |
| Zinc | 6.3 ug/L | 10 ug/L |
| Cryptosporidium | 0 | — |
| Giardia lamblia | 0.1 | — |
| Perfluoroheptanoic acid | 3.2 ng/L | — |
| PFBA | 8 ng/L | — |
| Alkalinity | 30 mg/L | — |
| Color | 4 | — |
| Hardness | 56 mg/L | — |
| Specific Conductance | 176 | — |
| Temperature | 71.6 | — |
| TOC | 7.45 mg/L | — |
| Total Dissolved Solids | 101 mg/L | — |
| PFHxA | 4.3 ng/L | — |
| PFPeA | 4.7 ng/L | — |
| PFBS | 3.8 ng/L | — |
What this report doesn't tell you
16 of the 27 contaminants a community water system normally reports do not appear anywhere in Charleston, SC's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
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 ↗