Hawaii Tap Water Quality Rankings 2026: 32nd in Nation | WaterQ
Hawaii ranks 32nd out of 50 states for drinking water quality, receiving an average score of 78 and a grade of B. With a population of approximately 1,500,007, the state's 66 water systems have recorded 1,527 violations.
Key Findings for Hawaii
Reviewing EPA SDWIS data for 2026, here's what defines Hawaii's water quality landscape:
- As a Pacific island region with unique volcanic geology, Hawaii's groundwater can be influenced by natural mineral deposits and volcanic elements filtering through basalt layers.
- The state's tourism-dependent infrastructure and localized agricultural activities can place seasonal demands on water distribution systems and contribute to runoff risks.
- Older distribution networks across the islands require ongoing infrastructure upgrades to prevent disinfection byproducts and maintain water quality standards for both residents and visitors.
Most Common Contaminants in Hawaii
Here's what Hawaii residents should know about the contaminants most relevant to their water:
Disinfection Byproducts
These compounds can form when chlorine used for water treatment reacts with naturally occurring organic matter in the water source. Regular monitoring is required to ensure these remain within safe limits.
Nitrate
Often associated with agricultural fertilizers or wastewater systems, nitrate can seep into shallow groundwater tables in rural or farming districts.
Total Coliform
Commonly used as an indicator of potential bacterial contamination, positive tests in island distribution systems typically prompt immediate flushing and re-testing.
Hawaii's Best and Worst Cities for Water Quality
Water quality can vary significantly between individual municipalities and water systems across the islands. We recommend searching for your specific municipality on our detailed state page to view localized testing results and violation history. Explore the full breakdown on our Hawaii water systems page.
What Hawaii Residents Should Do
Given Hawaii's 32nd place ranking, here's what matters most for residents:
- Look up your local water provider's annual Consumer Confidence Report (CCR) to review testing data.
- If your home is supplied by a private well, schedule periodic independent testing for mineral and bacterial contaminants.
- Consider using a certified water filtration system that targets the specific contaminant categories detected in your local area.
- Monitor the EPA violation history for your public water system to stay informed about active compliance issues.
Frequently Asked Questions
How does Hawaii water quality compare to other states?
Hawaii ranks 32nd out of 50 states in our drinking water quality assessment, receiving an average score of 78. This places the state in the middle tier nationally with an overall grade of B.
What are the most common contaminants in Hawaii tap water?
Common contaminants of concern include disinfection byproducts from treatment processes, nitrate from agricultural runoff, and bacterial indicators like total coliform. These issues are often linked to the region's island geography, agricultural land use, and volcanic geology.
Is it safe to drink tap water in Hawaii?
With a grade of B, Hawaii's tap water generally meets primary federal safety standards, though local systems do encounter compliance issues as shown by its 1,527 violations. Residents can check their specific local system's reports or use filtration for added precaution.
Source: EPA SDWIS 2026 Compliance Data and WaterQ National Database. For more information on our ranking process, visit our state rankings page.