Is Captain Cook, HI tap water safe?
The short answer
Neither of the 2 utilities serving Captain Cook has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s records.
South Kona, which serves the most people here, has 1 result above the health goal. The worst: Arsenic at 0.9 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Captain Cook’s ZIP codes, from EPA’s estimates.
- Open report
South Kona
Hawaii · serves 6,512 people · about 620 in Captain Cook
1 result above the health goal. The worst: Arsenic at 0.9 ppb, above the health goal.
No health-based violations since 2016
- Open report
North Kona
Hawaii · serves 29,581 people · about 180 in Captain Cook
2 results above the health goal. The worst: Uranium at 2.4 ppb, above the health goal.
No health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in South Kona’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Water testing near Captain Cook
No lab Hawaii certifies is within 75 miles of Captain Cook on the state’s list. Some take samples by mail; the state’s page lists them all.
All 12 certified labs for HawaiiWhich ZIP codes are in Captain Cook: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology.
Near Captain Cook
Other towns in Hawaii County with a page of their own.
What to do next
- Read South Kona’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- Filters for ArsenicRanked by certification and what they cost over five years.The best reverse osmosis systems, ranked
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water