Backflow testing in Hawaii
1 utility list · 11 companies · 16 testers on the 1 list that count testers. Your utility decides which testers it accepts, so start from the utility that sent your notice.
Utility lists in Hawaii
| Utility list | Area | Companies | Testers | vs national median | National rank (by companies) |
|---|---|---|---|---|---|
| Hawaii County Department of Water Supply | Hilo | 11 | 16 | 0.2× | 32 of 33 |
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC). National median: 57 companies per list across the 33 utility lists we hold (n=33). National rank 1 = the list naming the most companies; equal counts share a rank. Testers: only lists that name each company's testers carry a count. Not in the company counts: 1 entry for an individual tester with no company named; we count those but do not republish them.
How many testers each company has
| Utility list | Testers with a company | Companies | Testers per company | One-tester companies | Largest company (testers) | National rank (testers per company) |
|---|---|---|---|---|---|---|
| Hawaii County Department of Water Supply | 15 | 11 | 1.4 | 8 (73%) | 3 | 6 of 13 |
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC). Median across the 13 tester-level lists we hold: 1.3 testers per company (n=13); rank 1 = most testers per company. Counts only: we never publish testers’ names.
How current each list is
| Utility list | Version as printed | Date and age | Fetched (UTC) | We re-check it every |
|---|---|---|---|---|
| Hawaii County Department of Water Supply | “April 24, 2026” | 2026-04-24 (dated on the list), 194 days before we fetched it; 11 of 22 by recency | 2026-11-04 | 365 days |
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC). Median age at fetch across the 22 lists we hold that carry a date: 206 days (n=22); rank 1 = the most recently dated list. A month-only or two-digit version (for example “7.2026”) is shown as printed and not turned into a date.
Where the listed companies are based
11 companies on the Hawaii list print a town (11 of 11), spread over 8 towns. The most common:
- Kailua-Kona: 3 companies
- Hilo: 2 companies
- Honokaa: 1 company
- Honolulu: 1 company
- Kamuela: 1 company
- Mililani: 1 company
- Hawaii County Department of Water Supply: 2 of 11 companies with a printed town (18%) are in Hilo, the utility’s home city.
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC). Towns as each list prints them; a company named on two lists counts once.
What the lists print beyond names
- Hawaii County Department of Water Supply prints a tester certificate expiry date for 11 of 11 companies.
We do not republish expiry dates; open the utility’s own list to check them.
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC).
What kind of businesses are on the lists
The biggest difference from all the lists we hold: “backflow or cross-connection” appears in 36% of company names on the Hawaii list, against 24% across all of them.
| Company name contains | Companies (11) | Share | Share, all 2,590 companies we hold |
|---|---|---|---|
| Plumbing | 3 | 27% | 25% |
| Backflow or cross-connection | 4 | 36% | 24% |
| Fire | 0 | 0% | 17% |
| Irrigation, lawn, landscape or sprinkler | 0 | 0% | 10% |
| Mechanical, heating or air | 1 | 9% | 6% |
Computed from the list of Hawaii County Department of Water Supply, as fetched 2026-11-04 (UTC). A company named on two lists counts once. A name can match more than one row; 3 names here match none. The words say nothing about the quality of the work.
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