Water Quality in Johns Island, SC: 6 Violations — Grade A
Grade A · Score 86/100 · 2 water systems · Updated 2026-05-03
Johns Island's water meets all EPA standards with no health-based violations.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
SDWIS records for Johns Island, SC show 6 EPA violations documented for the local water supply — these span the full range of reportable events from health-based exceedances to monitoring and reporting lapses registered with the federal program.
Water Quality by ZIP Code in Johns Island
Water quality varies across Johns Island's 2 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 29455 | B | 74 | 3 | 0 | View report → |
| 29457 | A | 98 | 3 | 0 | View report → |
Water Quality Overview
Johns Island, South Carolina receives a water quality grade of A with an overall score of 86 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 2 water systems serving Johns Island have accumulated 6 EPA violations (all monitoring/reporting type). These violations are tracked across 2 ZIP codes serving approximately 28,531 people.
What Grade A Means
A grade of A indicates excellent compliance with EPA drinking water standards. Johns Island's water systems have maintained strong performance in both contaminant monitoring and regulatory compliance.
Lead Levels
The average 90th percentile lead level across Johns Island water systems is 0.0020 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Water Systems Serving Johns Island
Johns Island is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 28,531 people across 2 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 12 enforcement actions against water systems serving Johns Island. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Johns Island
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Johns Island Water Systems
The following contaminants have been detected or caused violations across Johns Island's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | N/A | 2 | 2 | No |
| E. coli | Microbiological | N/A | 2 | 2 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 6 enforcement actions against water systems serving Johns Island. Recent actions:
| Date | Action Type |
|---|---|
| 2025-01-29 | State Informal Action |
| 2024-03-08 | State Informal Action |
| 2024-03-08 | State Informal Enforcement |
| 2024-03-06 | State Order Extension |
| 2024-02-26 | State Informal Action |
| 2024-02-26 | State Informal Enforcement |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-01-29.
Johns Island vs. Nearby South Carolina Cities
How Johns Island's water quality compares to similar cities in South Carolina:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Johns Island | A | 6 | 2 | 28,531 |
| Fort Mill | B | 12 | 5 | 28,541 |
| Westminster | B | 2 | 5 | 28,413 |
| Enoree | D | 0 | 1 | 28,897 |
Common Questions About Johns Island Water
These are the most common questions residents search for about water quality in Johns Island, South Carolina:
Is Johns Island water hard or soft? Water hardness varies by source. Johns Island's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Johns Island tap water? Johns Island's water receives a grade of A (86/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Johns Island? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Johns Island vs. South Carolina Average
Understanding how Johns Island compares to the broader South Carolina average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Johns Island.
ZIP Codes in Johns Island
Johns Island spans 2 ZIP codes. The ZIP with the lowest water quality score is 29455. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
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
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade A is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.