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Private wells

Hawaii well water: what to test for

The USGS national arsenic and nitrate models used on our county pages don’t cover Hawaii, so there are no modelled figures here. A lab test of your own well is the way to know what’s in it.

Find a certified lab

What to test your well for, and how often

“Test your well water at least once every year for total coliform bacteria, nitrates, total dissolved solids, and pH level.” CDC

  1. Total coliform bacteriaEvery year · EPA and CDC
  2. NitrateEvery year · EPA and CDC
  3. Total dissolved solidsEvery year · EPA and CDC
  4. pHEvery year · EPA and CDC
  5. ArsenicAsk your local health department how often · CDC and USGS model

    Arsenic occurs naturally in groundwater in many areas. CDC suggests asking your local health department whether to test for it.

Test again sooner (CDC):

  • After flooding or land disturbance near the well
  • After the well is repaired or a part is replaced
  • When the water’s taste, colour or smell changes
  • If someone in the home is pregnant or nursing
  • When an infant or child joins the household

Sources: EPA: Private Drinking Water Wells · EPA: Protect Your Home’s Water · CDC: Guidelines for Testing Well Water

Where to test

Hawaiʻi Department of Health certifies the laboratories that test drinking water in Hawaii.

Find a certified lab in Hawaii →

From EPA’s list of state certification programs (August 2025).

Test your own well

Screening tells you if something is worth a closer look; a lab result is the number you can act on.

As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure.

  • Lab-certified results

    ETR Labs Basic Water Quality Test Kit

    ETR Laboratories

    50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria

    What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.

    Check price on Amazon

  • Screening: quick check, not lab-grade

    Watersafe Drinking Water Test Kit

    Silver Lake Research

    Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH

    • Turnaround: Minutes; the bacteria test can take up to 48 hours

    What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.

    Check price on Amazon

A mail-in kit’s lab is accredited (ISO/IEC 17025) but may not be certified by your state. For a home sale, a loan, or a health-department follow-up, use a state-certified lab.

Your state health or environmental agency may also publish local well-water guidance.