Backflow testing in Ohio
1 utility list · 144 companies · 349 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 Ohio
| Utility list | Area | Companies | Testers | vs national median | National rank (by companies) |
|---|---|---|---|---|---|
| City of Columbus Dept. of Public Utilities, Backflow Compliance Office | Columbus | 144 | 349 | 2.5× | 5 of 33 |
Computed from the list of City of Columbus Dept. of Public Utilities, Backflow Compliance Office, as fetched 2026-11-15 (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: 3 entries for an individual tester with no company named and 7 entries for companies named after a person; 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) |
|---|---|---|---|---|---|---|
| City of Columbus Dept. of Public Utilities, Backflow Compliance Office | 339 | 144 | 2.4 | 68 (47%) | 19 | 1 of 13 |
Computed from the list of City of Columbus Dept. of Public Utilities, Backflow Compliance Office, as fetched 2026-11-15 (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 |
|---|---|---|---|---|
| City of Columbus Dept. of Public Utilities, Backflow Compliance Office | “Created 2026-10-30; valid through 2026-11-14” | 2026-10-30 (dated on the list), 16 days before we fetched it; 2 of 22 by recency · Old list | 2026-11-15 | 7 days |
Computed from the list of City of Columbus Dept. of Public Utilities, Backflow Compliance Office, as fetched 2026-11-15 (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
142 companies on the Ohio list print a town (142 of 144), spread over 46 towns. The most common:
- Columbus: 42 companies
- Grove City: 9 companies
- Hilliard: 6 companies
- Westerville: 6 companies
- Dublin: 5 companies
- London: 5 companies
- City of Columbus Dept. of Public Utilities, Backflow Compliance Office: 42 of 142 companies with a printed town (30%) are in Columbus, the utility’s home city.
Based outside Ohio: 1 company in Indiana, 1 company in West Virginia.
Computed from the list of City of Columbus Dept. of Public Utilities, Backflow Compliance Office, as fetched 2026-11-15 (UTC). Towns as each list prints them; a company named on two lists counts once.
What kind of businesses are on the lists
The biggest difference from all the lists we hold: “mechanical, heating or air” appears in 17% of company names on the Ohio list, against 6% across all of them.
| Company name contains | Companies (144) | Share | Share, all 2,590 companies we hold |
|---|---|---|---|
| Plumbing | 44 | 31% | 25% |
| Backflow or cross-connection | 10 | 7% | 24% |
| Fire | 26 | 18% | 17% |
| Irrigation, lawn, landscape or sprinkler | 6 | 4% | 10% |
| Mechanical, heating or air | 25 | 17% | 6% |
Computed from the list of City of Columbus Dept. of Public Utilities, Backflow Compliance Office, as fetched 2026-11-15 (UTC). A company named on two lists counts once. A name can match more than one row; 42 names here match none. The words say nothing about the quality of the work.
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