Water Quality in Key West, FL: 33 Violations — Grade C
Grade C · Score 62/100 · 1 water system · Updated 2026-05-03
Key West's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
The public EPA compliance record for Key West, FL holds 33 documented water violations — sourced from the federal Safe Drinking Water Information System, which tracks every reportable event for registered public water systems in the state.
Water Quality by ZIP Code in Key West
Water quality varies across Key West's 3 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 33040 | C | 61 | 11 | 0 | View report → |
| 33041 | B | 81 | 11 | 0 | View report → |
| 33045 | B | 81 | 11 | 0 | View report → |
Water Quality Overview
Key West, Florida receives a water quality grade of C with an overall score of 62 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 1 water system serving Key West have accumulated 33 EPA violations (all monitoring/reporting type). These violations are tracked across 3 ZIP codes serving approximately 86,000 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Key West's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Key West water systems is 0.0040 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 68% of homes built before 1986, Key West has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Key West is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Key West
Key West is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 86,000 people across 3 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
How to Check Your Water in Key West
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 Key West Water Systems
The following contaminants have been detected or caused violations across Key West's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Lead | Inorganic | 0.015 mg/L | 3 | 3 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 3 | 3 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 3 | 3 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 3 | 3 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Key West vs. Nearby Florida Cities
How Key West's water quality compares to similar cities in Florida:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Key West | C | 33 | 1 | 86,000 |
| Big Pine Key | D | 0 | 1 | 86,000 |
| Marathon Shores | C | 0 | 1 | 86,000 |
| Summerland Key | D | 0 | 1 | 86,000 |
Recommended Water Filters for Key West
Based on contaminants detected in Key West's water supply, these filter types are recommended:
Granular Activated Carbon (GAC, whole-house or under-sink)
- Removes: Chloramine
- Effectiveness: 95-99%
- Cost range: $100–$600
- Certification: NSF/ANSI 42
- Recommended products:
- Aquasana AQ-5200
- Waterdrop Chubby Pitcher
- Berkey Travel
Water Quality by ZIP Code in Key West
Water quality varies across Key West's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
Common Questions About Key West Water
These are the most common questions residents search for about water quality in Key West, Florida:
Is Key West water hard or soft? Water hardness varies by source. Key West's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink Key West tap water? Key West's water receives a grade of C (62/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Key West? Based on detected contaminants, a granular activated carbon (gac, whole-house or under-sink) filter is most recommended. See our Water Filter Matcher for personalized recommendations.
Key West vs. Florida Average
Understanding how Key West compares to the broader Florida 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 Key West.
ZIP Codes in Key West
Key West spans 3 ZIP codes. The ZIP with the lowest water quality score is 33040. 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.