Hawaii · about 631,389 people · groundwater
PFHxS was found in 1 of 644 samples taken between May 2023 and Dec 2025. Every value was below the 2024 federal limits.
Research monitoring by EPA (UCMR 5), samples May 2023 – Dec 2025 · read 2026-10-31 · next check: Your utility's yearly water quality report is due by 1 July each year. EPA's next national monitoring round (UCMR 6) is planned for 2028–2030.
| Substance | Found in | Highest | 2024 limit |
|---|---|---|---|
| PFOA | 0 of 92 | below 4 ng/L | 4 ng/L |
| PFOS | 0 of 92 | below 4 ng/L | 4 ng/L |
| PFHxS | 1 of 92 | 3 ng/L | 10 ng/L |
| PFNA | 0 of 92 | below 4 ng/L | 10 ng/L |
| HFPO-DA (GenX) | 0 of 92 | below 5 ng/L | 10 ng/L |
| PFBS | 0 of 92 | below 3 ng/L | none |
| lithium | 0 of 92 | below 9 µg/L | none |
"Found in" counts samples above the laboratory reporting level. ng/L = nanograms per litre (parts per trillion); lithium is shown in µg/L as EPA reports it. "Highest" is the single highest sample at any entry point or tap, not an average. "Below the reporting level" means the laboratory did not find the substance above its minimum reporting level (MRL), the smallest amount the EPA method reports. It is a laboratory threshold, not a health threshold, and it is not the same as zero.
UCMR 5 was a one-time national monitoring programme (2023–2025). The results are a snapshot at the system's entry points or taps on the sample dates, not a continuous measurement and not a compliance record.
In April 2024 EPA set the first national limits for PFAS in drinking water: 4.0 ng/L for PFOA and PFOS; 10 ng/L for PFHxS, PFNA and HFPO-DA (GenX); plus a hazard index for mixtures. PFBS has no limit of its own. Lithium has no federal limit; UCMR 5 measured it for information. On 20 May 2026 EPA proposed removing the limits for PFHxS, PFNA and HFPO-DA and the hazard index; that proposal was not final when we last checked (5 Nov 2026). The PFOA and PFOS limits are not affected by it. We show the 2024 numbers as written; check EPA's PFAS rule page for the current state. EPA PFAS rule page.
Not yet on this page: the system's compliance record (violations) and its lead sampling results from EPA's SDWIS database. We will add them with their own dates and wording. Until then, the two closer sources are the utility's yearly report and EPA's public databases, linked below.
Phone and website: on your water bill, or through EPA's CCR finder above. We list no contact details we have not verified.
Types, not brands. Yearly cost of the replaceable filters at average use (about 0.23 gallons of drinking and cooking water per person per day, EPA Exposure Factors Handbook). Figures from our cost page, prices read 27–30 October 2026. Your numbers stay in your browser.
| Buy nothing one of the outcomes: your utility's report and your own tap decide | $0 a year |
| Faucet-type filter cartridge listed for 100 gallons, about $14 | $35 |
| Pitcher filter cartridge listed for 120 gallons, about $17.50, six-month limit | $37 |
| Under-sink reverse osmosis filters, power and drain water; mostly time-limited | $178 |
Which type fits depends on what, if anything, your own water report shows; filters certified to NSF/ANSI 53 or 58 carry a tested claim for the substance named on the listing. Our list by type: filters certified for lead and PFAS.
Hnl-Windward-Pearl Harbor (EPA ID HI0000331) serves about 631,389 people through about 106,491 service connections, mainly from groundwater. The name on your water bill is the one that counts; a ZIP code can be served by more than one system.
PFHxS was found in 1 of 644 samples taken between May 2023 and Dec 2025. Every value was below the 2024 federal limits. "Below the reporting level" means the laboratory did not find the substance above its minimum reporting level (MRL), the smallest amount the EPA method reports. It is a laboratory threshold, not a health threshold, and it is not the same as zero.
No. We publish the public test results with their dates and explain what they do and do not cover. What reaches your glass also depends on the pipes in your building, and anyone with a health condition should ask their clinician about their water. The two closer sources are the utility's yearly report and a test at your own tap.
A single sample above a 2024 limit is a measurement, not a violation. Compliance is judged on running yearly averages, and water systems have until 2029 to meet the limits. On 20 May 2026 EPA proposed giving qualifying systems until 2031 for PFOA and PFOS and removing the limits for PFHxS, PFNA and HFPO-DA; those proposals were not final when we last checked (5 Nov 2026).
Every community water system must deliver a Consumer Confidence Report to its customers by 1 July each year. Use EPA's CCR finder or the utility's own website; the report covers more substances than this page.
It depends on the number of people and the filter type, not on the brand. For 3 people at average use, a faucet-type filter costs about $35 a year in cartridges and a pitcher about $37; an under-sink reverse-osmosis unit about $178 a year in filters. Buying nothing costs $0 and is one of the outcomes.