Johns Island, SC: 6 Violations — 86/100 (2026)
2 ZIP codes · 3 water systems · Updated 2026-06-03
Water systems serving Johns Island hold a strong EPA compliance record — the city places among the better-performing areas in SC with few health-based violations on file.
How Johns Island Compares
Data: EPA SDWIS Last verified: 2026-06-03
Johns Island Water: The Quick Version
- Your city's water systems recorded 6 violations in the past 5 years.
- Average lead level: 0.002 mg/L.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 11.36.
Water Systems Serving Johns Island
With 3 utilities splitting service in Johns Island, SC, water accountability is distributed across 3 systems on the federal record.
Overview
We track water quality and home safety data for 2 ZIP codes in Johns Island, South Carolina (population ~26,308), covering 3 community water systems serving approximately 355,953 people region-wide.
2 of 2 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Johns Island: A (86/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Johns Island water systems draw from: Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0020 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 2 ZIP codes
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Consumer Confidence Report Rule | Reporting | 3 | 2 |
| Revised Total Coliform Rule | Microbiological | 3 | 2 |
| E. coli | Microbiological | 3 | 2 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 29455 | B | 3 | 0 | St John's Water (sc1020002) |
| 29457 | A | 3 | 0 | St John's Water (sc1020002) |
All ZIP Codes in Johns Island
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for Johns Island
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Key Contaminants Detected in Johns Island
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Johns Island: Remediation Cost in Perspective
At current valuations, Johns Island sits in the low remediation-share tier — the equity impact of fixing documented issues is proportionally minor.
Remediation costs in Johns Island are relatively low compared to home values. The $800–$1,700 estimated range is a small fraction of median property value. Home values are 142% above the South Carolina average.
Protecting Children from Lead in Johns Island
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Lead risk in Johns Island appears low overall, but individual homes may differ. Testing is the only way to confirm your water's lead content.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Johns Island
Substantially more flood exposure than most communities appears in Johns Island's NFIP record — 1029 documented claims and 50% of ZIP codes in FEMA flood zones. That exposure level makes the water-quality implications of flooding an active planning consideration rather than a background one.
Johns Island has a significant flood history with 1,029 FEMA flood insurance claims on record, averaging $4,124 per claim. With 50% of ZIP codes in FEMA-designated flood zones, flood risk is a major concern for homeowners and water quality.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,200</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Johns Island, SC