CITY REPORT SC

Johns Island, SC: 3 Violations - Home Safety 82/100

2 ZIP codes · 4 water systems · Updated

ZipCheckup grade for Johns Island: B.

This ZIP looks solid, with a few items worth a quick check.

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

Johns Island82/100
South Carolina avg80/100
National avg73/100

Data: EPA SDWIS

2
ZIP Codes
4
Water Systems
1
ZIPs with Violations
B · 82
Avg Safety Score
Zone 3
Radon Risk (Low)
$500K
Median Home Value
$1,200
Est. Remediation (0.2% of home value)

Johns Island Water: The Quick Version

  • Your city's water systems recorded 3 violations in the past 5 years.
  • Average lead level: 0.004 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 4 systems on the federal record.

Overview

We track home safety data for 2 ZIP codes in Johns Island, South Carolina (population ~26,308), covering 4 community water systems serving approximately 365,503 people region-wide. The EPA snapshots used for this build directly map water systems to 1 of 2 ZIP codes.

1 of 1 ZIP code with a reported violation count in the available EPA record (100%) have recorded EPA violations. The available record reports no health-based violations for this measured scope.

Home Safety Score

Average Home Safety Score for Johns Island: B (82/100)

Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:

Factor What It Measures
Water Quality EPA violations and compliance history
PFAS MCL Screen UCMR 5 testing against the covered federal MCLs
Radon Risk EPA radon zone classification
Annual AQI EPA AirData county-year median with at least 90 observed days

Water Sources

Johns Island water systems draw from: Surface water.

Lead & Copper

  • Average lead level (90th percentile): 0.0040 mg/L (EPA action level: 0.015 mg/L)
  • 0 of 1 ZIP code with known status 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 2 1
E. coli Microbiological 2 1
Revised Total Coliform Rule Microbiological 2 1

Areas with Most Violations

ZIP Code Safety Score Violations Health-Based System
29455 B 3 0 St John's Water (sc1020002)

All ZIP Codes in Johns Island

Data Sources

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

CDC Health Data for Johns Island

8.8%
Asthma (US: 9.8%)
11.4%
Diabetes (US: 10.4%)
14.4%
Poor Mental Health (US: 14.8%)

Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.

Compared to National Average

Asthma 8.8% ↓
Diabetes 11.4% ↑
Mental Health 14.4% ↓

Vertical line = national average. ■ Above national · ■ Below national

Key Contaminants Detected in Johns Island

Consumer Confidence Report Rule 2 violations
Reporting
E. coli 2 violations
Microbiological
Gastrointestinal illness, potentially fatal
Revised Total Coliform Rule 2 violations
Microbiological
Indicates possible bacterial contamination

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.

Median Home Value
$499,500
Est. Remediation
$1,200
Remediation as % of home value 0.2%

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

0.004
mg/L Avg Lead (Limit: 0.015)

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.

Historical Flood-Claim Evidence for Johns Island

1,029
Total FEMA Flood Claims
$10,152
Avg Reported Sum With Payment Data
100%
A/V Share of Claim-Record ZIPs

Historical NFIP data for Johns Island contains 1,029 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $10,152. Among ZIP codes with claim records, 100% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.

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. The <strong>$1,200</strong> remediation estimate shown here excludes flood insurance and is not derived from NFIP claim count.

Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.

Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.

Deep Dive Reports

Detailed analysis for Johns Island, SC

Frequently Asked Questions

What does the Home Safety Score mean for Johns Island, SC?
Johns Island has an average Home Safety Score of 82/100 (Grade B) under model 4.0.0. The score combines EPA SDWIS identity plus accepted ECHO SDWA lifecycle-based water compliance, the PFAS MCL screen, EPA radon zone, and annual EPA AQI, and is published only when all required domains are observed. 3 EPA violations have been recorded. Check individual ZIP code reports for component details.
How many water violations does Johns Island have?
Johns Island water systems have a total of 3 EPA violations. Violations are tracked across 2 ZIP codes.
Does Johns Island water have lead?
The average 90th-percentile lead level in Johns Island is 0.004 mg/L. This is below the EPA action level of 0.015 mg/L. Lead levels can vary by home - testing is recommended especially in older properties.
How does Johns Island compare to South Carolina average?
Johns Island has an average Home Safety Score of 82/100, which is above the South Carolina state average of 80/100 for the same model series.
How many water systems serve Johns Island?
Johns Island is served by 4 public water systems across 2 ZIP codes, serving approximately 26,308 people.
How much does it cost to fix water issues in Johns Island?
Estimated remediation costs in Johns Island average $1,200 per household, ranging from $800 to $1,700. Costs include filtration, pipe replacement, radon mitigation, and flood protection.
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How to cite this page

APA ZipCheckup. (2026). Johns Island, SC: 3 Violations - Home Safety 82/100. https://zipcheckup.com/cities/sc/johns-island/
BibTeX 
@misc{zipcheckup-cities-sc-johns-island,
  author = {{ZipCheckup}},
  title  = {{Johns Island, SC: 3 Violations - Home Safety 82/100}},
  year   = {2026},
  url    = {https://zipcheckup.com/cities/sc/johns-island/}
}

Page version: August 2026.

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