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Updated 2026-09-16
State water report

Hawaii Water Quality: 11 Cities Ranked by the Records

Water quality across 11 cities in Hawaii, drawn from EPA drinking-water records. Each city page shows the measured contaminants and a reproducible Purity Score.

Finding by finding

What Hawaii's records show

Counts of cities whose serving system reported each result. There is no statewide score: PurityMap does not average local records into a statewide safety verdict.

PFAS above a 2024 limit

MCL

0of 11 cities

Cities whose system reported a PFAS above its federal limit.

PFOS in Hawaii →
City rankings

Hawaii cities ranked by the records

Highest first. A summary of each serving system’s record, not a safety verdict.

  1. 1
    Waipahu-Ewa-WaianaeWAIPAHU-EWA-WAIANAE · HI0000335
    Report →
  2. 2
    WailukuWAILUKU · HI0000212
    Report →
  3. 3
    MililaniMILILANI · HI0000367
    Report →
  4. 4
    KapaaLIHUE-KAPAA · HI0000400
    Report →
  5. 5
    North KonaNORTH KONA · HI0000131
    Report →
  6. 6
    WahiawaWAHIAWA · HI0000333
    Report →
  7. 7
    Kalaheo-KoloaKALAHEO-KOLOA · HI0000434
    Report →
  8. 8
    Waipio HeightsWAIPIO HEIGHTS · HI0000334
    Report →
  9. 9
    LahainaLAHAINA · HI0000214
    Report →
  10. 10
    MakawaoMAKAWAO · HI0000213
    Report →

Showing the top 10 of 11 scored cities.

See all 11 in the table

11 cities, highest Purity Score first

  1. 1Waipahu-Ewa-Waianae
    WAIPAHU-EWA-WAIANAE · PWSID HI0000335 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    PFPeA 3.3 ng/L detected, no federal or state limitDetected
  2. 2Wailuku
    WAILUKU · PWSID HI0000212 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  3. 3Mililani
    MILILANI · PWSID HI0000367 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  4. 4Kapaa
    LIHUE-KAPAA · PWSID HI0000400 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  5. 5North Kona
    NORTH KONA · PWSID HI0000131 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  6. 6Wahiawa
    WAHIAWA · PWSID HI0000333 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  7. 7Kalaheo-Koloa
    KALAHEO-KOLOA · PWSID HI0000434 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  8. 8Waipio Heights
    WAIPIO HEIGHTS · PWSID HI0000334 · Purity Score 100/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detectedNot detected
  9. 9Lahaina
    LAHAINA · PWSID HI0000214 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detected; lead 0.78 µg/LDetected
  10. 10Makawao
    MAKAWAO · PWSID HI0000213 · Purity Score 98/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    No PFAS detected; lead 0.88 µg/LDetected
  11. 11Hnl-Windward-Pearl Harbor
    HNL-WINDWARD-PEARL HARBOR · PWSID HI0000331 · Purity Score 95/100 (Excellent) · Confidence: moderate · Assessed at the water-system level
    PFAS detected below EPA limitsDetected
End of list.

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no state score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works. See how Hawaii compares with other states.

By contaminant

lead in Hawaii

Counties

Hawaii counties

3 counties with city reports
Suppliers

Largest water systems

  • HNL-WINDWARD-PEARL HARBORHnl-Windward-Pearl Harbor · HI0000331 · 631,389 served
  • WAIPAHU-EWA-WAIANAEWaipahu-Ewa-Waianae · HI0000335 · 217,479 served
  • WAILUKUWailuku · HI0000212 · 74,511 served
  • MILILANIMililani · HI0000367 · 50,573 served
  • LIHUE-KAPAAKapaa · HI0000400 · 34,854 served
  • MAKAWAOMakawao · HI0000213 · 29,868 served
All water systems →
Full indexAll 11 Hawaii city reports, A–Z
Next step

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Plumbing inside a building can add lead and change what reaches your glass.

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Only after a city report names a finding, match a treatment certified for it.

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Questions

Hawaii water, frequently asked

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How does Hawaii tap water compare across cities?

PurityMap ranks 11 cities in Hawaii by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Waipahu-Ewa-Waianae's main water system: WAIPAHU-EWA-WAIANAE · PWSID HI0000335 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Hawaii cities have PFAS above the federal limit?

None of the 11 Hawaii cities on record had a regulated PFAS above the 2024 federal limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 2.

Is there lead in Hawaii tap water?

Utilities report lead as a 90th-percentile result from home taps. 2 of 11 Hawaii cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

Limits, sources and corrections

A statewide page cannot tell you what reaches a specific address. Water quality varies by supplier, sampling period and household plumbing; open a city report for the evidence behind a local result.

Sources: EPA UCMR 5 (PFAS, 2024), SDWIS Lead and Copper Rule 90th-percentile results and health-based violations, and utility Consumer Confidence Reports where on file. Every city report links its dated source records.

Updated 2026-09-16. How PurityMap analyzes water data · Report an error