Hawaii Water Quality Report: 22 Water-System Violations Mapped to 77 ZIPs
130 water systems · 77 ZIP codes · 22 violations
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO
ZipCheckup tracks EPA drinking-water compliance for 130 public water systems serving 77 ZIP codes in Hawaii. The state record shows 22 EPA violations, 0 health-based.
City Water Quality Map: Hawaii
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Cities with Most Violations in Hawaii
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Lanai City | 11 | 1 | 3,333 | Details → | |
| 2 | Hoolehua | 2 | 1 | 1,576 | Details → | |
| 3 | Kualapuu | 2 | 1 | 800 | Details → | |
| 4 | Maunaloa | 2 | 1 | 548 | Details → | |
| 5 | Kailua Kona | 1 | 1 | 40,805 | Details → | |
| 6 | Pearl City | 1 | 3 | 37,740 | Details → | |
| 7 | Kamuela | 1 | 5 | 13,326 | Details → | |
| 8 | Holualoa | 1 | 1 | 4,672 | Details → | |
| 9 | Kealakekua | 1 | 2 | 3,137 | Details → |
Most Common Contaminants in Hawaii
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 10 | 7 | No |
| Interim Enhanced Surface Water Treatment Rule | Treatment Technique | 1 | 1 | No |
| Arsenic | Inorganic | 1 | 1 | No |
| Barium | Inorganic | 1 | 1 | No |
| Cadmium | Inorganic | 1 | 1 | No |
| Chromium | Inorganic | 1 | 1 | No |
| Mercury | Inorganic | 1 | 1 | No |
| Nickel | Inorganic | 1 | 1 | No |
| Selenium | Inorganic | 1 | 1 | No |
| Antimony | Inorganic | 1 | 1 | No |
Water Quality Overview
Hawaii has 130 community water systems represented across 77 directly mapped ZIP records. The associated city records cover approximately 2,058,409 people. The available records contain 22 EPA violations, including 0 health-based violations.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 0 | 0.0% |
| Monitoring/Reporting | 22 | 100.0% |
| Total | 22 | 100% |
Health-based violations are MCL, MRDL (disinfectant) and treatment-technique violations. Monitoring violations indicate failures to test or report - these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Hawaii have the highest number of EPA violations:
| Rank | City | Violations | Water Systems | Population |
|---|---|---|---|---|
| 1 | Lanai City | 11 | 1 | 3,333 |
| 2 | Hoolehua | 2 | 1 | 1,576 |
| 3 | Kualapuu | 2 | 1 | 800 |
| 4 | Maunaloa | 2 | 1 | 548 |
| 5 | Kailua Kona | 1 | 1 | 40,805 |
| 6 | Pearl City | 1 | 3 | 37,740 |
| 7 | Kamuela | 1 | 5 | 13,326 |
| 8 | Holualoa | 1 | 1 | 4,672 |
| 9 | Kealakekua | 1 | 2 | 3,137 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Most Common Contaminants
The following contaminants have caused the most violations across Hawaii water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 10 | 7 | No |
| Interim Enhanced Surface Water Treatment Rule | Treatment Technique | 1 | 1 | No |
| Arsenic | Inorganic | 1 | 1 | No |
| Barium | Inorganic | 1 | 1 | No |
| Cadmium | Inorganic | 1 | 1 | No |
| Chromium | Inorganic | 1 | 1 | No |
| Mercury | Inorganic | 1 | 1 | No |
| Antimony | Inorganic | 1 | 1 | No |
| Public Notice Rule | Reporting | 1 | 1 | No |
How to Check Your Water in Hawaii
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the separate Home Safety Score is a multi-source index
Request your CCR - every water utility must provide an annual Consumer Confidence Report
Get a home test - certified kits ($20-$50) or professional lab tests ($150-$400)
Consider filtration - NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken enforcement actions against water systems in Hawaii. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grades summarize ZipCheckup's scoring inputs; review the underlying records for specific issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Hawaii?
Records for 130 community water systems mapped to ZIPs in Hawaii show 22 reported violations, including 0 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many violations are on record for water systems serving Hawaii?
Hawaii has 22 EPA violations on record across 77 ZIP codes; 0 are classified as health-based violations. The remainder are monitoring or reporting violations.
Which city in Hawaii has the worst water quality?
Lanai City, HI has the most recorded EPA violations (11) among the cities with mapped water systems in Hawaii in our data. Check your water supplier's report and test your tap water for the most accurate picture of your local water quality.
Which city in Hawaii has the best water quality?
Violation records vary by water system across Hawaii. Check individual city reports for details.
What contaminants are found in Hawaii drinking water?
EPA regulates over 90 drinking-water contaminants nationally; water systems in Hawaii monitor those applicable to each system, which can include lead, copper, nitrate, disinfection byproducts, and bacteria. The most common violations vary by region - check your ZIP code for contaminant-specific data.