BackflowNear Test-Due Reminder

Backflow testing companies in Hawaii

From County of Hawaii Department of Water Supply's list of companies approved to test backflow assemblies in its water system, read April 24, 2026. Hawaii publishes no statewide tester list we can use, so we start with its largest utility lists.

11 companies on the utility list
5 listed here, phones checked on Google

The lists we use in Hawaii

Being on a utility's list means that utility lets the company file backflow test reports in its system. It is not a state license. See Hawaii backflow rules.

Backflow testing businesses in Hawaii

Ranked by our quality score: on the utility's current list, a phone that matches the business's Google profile, and a website. Nobody can pay to move up.

What the badges mean
✓ HI Utility-Approved Tester Verified On the city list
The company is on a water utility's own approved list (the second badge names the list). That is the utility's approval, not a state license, and it counts for that utility.
3 certified testers
How many certified testers the roster lists at this business.
★ 4.8 (25 reviews)
The Google rating, shown as Google reports it. It does not change the order.

Order is by our quality score, never by payment. How we verify listings.

Commercial Plumbing Inc

100/100
✓ HI Utility-Approved Tester Verified #0965 ★ 3.9 (48 reviews) 2 certified testersOn Hawaii County Department of Water Supply list Backflow Testing

1820 Colburn St, Honolulu, HI 96819

Call (808) 845-4112 Details Website
Verified Oct 2026 · Unclaimed listing

Qualified Plumbing LLC

80/100
✓ HI Utility-Approved Tester Verified #0576 On Hawaii County Department of Water Supply list Backflow Testing

16-158 Kalara St, Keaau, HI 96749

Call (808) 934-7398 Details
Verified Oct 2026 · Unclaimed listing

Every listed backflow testing company, A to Z

Questions

Where do these Hawaii backflow testing companies come from?

Hawaii publishes no statewide list of backflow testers that we can use, so every business here is on the approved list of County of Hawaii Department of Water Supply: companies allowed to file backflow test reports in that water system. We read the list on April 24, 2026 and checked each company's phone against its Google profile.

Who is allowed to test a backflow preventer in Hawaii?

A tester certified as Hawaii's rules require, and usually one your water utility accepts. Our Hawaii rules guide links the state rule. Ask any company for the tester's certificate number before the test.

How often does a backflow assembly need testing?

Most water utilities require testable backflow assemblies to be tested at installation and then every year. Your utility's notice gives your deadline and how the report is filed.

Never miss your annual backflow test

Most water utilities require the backflow assembly on an irrigation, fire or commercial line to be tested every year, and a missed test can mean a shutoff notice. Tell us when yours was last tested and we'll text you a month before it is due, with certified local testers ready to book.

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