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Hiring a plumber: 5 red flags and 10 questions, checked against plumbing permits in 43 cities

To hire a plumber, check three things: a plumbing license (and, in most states, the master plumber behind it) that is active today, a plumbing permit pulled in the plumber's own name, and a permit history in your city that mostly reaches a final inspection. In Cincinnati, 258 firms pulled 6,119 plumbing permits in three years, 85.9% of those a year or more old reached a final, and the usual one was filed at $3,500. In Cleveland, only 58.6% did. Where your plumber sits against its own city is the number that matters.

By Contractor Records · data through October 17, 2026

Who licenses plumbers in the states we cover

We hold plumbing permits for 43 cities in 19 states. Plumbers are licensed in all of them, but not always by the contractor board.

State License to ask for Look it up
Arizona ROC specialty residential license whose class covers plumbing ROC Contractor Search
California CSLB C-36 Plumbing CSLB Check a License
Colorado DORA State Plumbing Board license; Colorado Springs also requires PPRBD registration DORA Verify a License
Florida DBPR plumbing contractor, certified or registered MyFloridaLicense
Hawaii C-37 plumbing PVL search
Iowa PMSB contractor license, plus contractor registration PMSB search
Illinois Illinois Department of Public Health plumbing license; Chicago trade license in the city Local IDPH office; Chicago trade contractors
Massachusetts Master or journeyman plumber or gas fitter, Board of State Examiners of Plumbers and Gas Fitters eLIPSE
Minnesota DLI plumbing contractor license, $25,000 bond, master plumber DLI iMS
North Carolina Plumbing, Heating & Fire Sprinkler board license; "minor repairs and service work" are exempt Board search
North Dakota State Plumbing Board license Ask the board; we found no public online lookup
Nevada NSCB C-classification covering plumbing, with a monetary limit NSCB search
New York City DOB Licensed Master Plumber DOB plumbers look-up
Ohio OCILB plumbing license, required by Cleveland and Cincinnati registration OCILB lookup, Cincinnati search
Oregon CCB license plus a BCD plumbing license CCB, BCD
Tennessee CMC-A Plumbing for jobs of $25,000 and up verify.tn.gov
Texas State Board of Plumbing Examiners license under a Responsible Master Plumber TSBPE search
Virginia DPOR contractor license with the plumbing (PLB) specialty, plus the plumber's tradesman license DPOR License Lookup
Washington L&I contractor registration plus the plumbing licensing L&I requires on top L&I Verify

Ten questions to ask a plumber, and how to check each answer

Ask A good answer How to check it
1. What is your plumbing license number? A number in the firm's name, in a plumbing class The board in the table above
2. Who is the master plumber on the license? A named person who works for this firm The board record
3. Does this job need a permit, and who pulls it? "Yes, we do" for a water heater, gas line, repipe or sewer line The permit on the city portal
4. Who does the gas work? This firm under its license, or a named licensed gas fitter The board record (gas is a separate license in Massachusetts)
5. How many plumbing permits have you pulled here in three years? A number The firm's page here: search by name
6. How many passed final? Near your city's share (table below) Finished share on the firm page
7. How long from permit to final, usually? Near your city's usual days Days to final on the firm page
8. Is it a flat price or time and materials? Flat for a defined job, with a written cap if hourly The quote
9. What is the deposit? Small and tied to stages; in California no more than $1,000 or 10% down The contract (B&P § 7159.5)
10. What happens if you open the wall and find more? A written change-order process with prices before work The contract

Red flags the permit record can show

City Plumbing permits Firms Usual filed value Usual days to final Reached final 10th-percentile firm Firms under 70% finished
Miami, FL 7,927 1,002 $4,900 127 90.8% 79.5% 1 of 84
Cape Coral, FL 1,461 186 $4,985 71 91.3% 83.5% 1 of 30
Arlington, VA 6,454 448 $3,000 75 83.3% 60.9% 19 of 106
Cincinnati, OH 6,119 258 $3,500 90 85.9% 73.0% 4 of 98
Cleveland, OH 5,315 296 $2,500 234 58.6% 36.5% 41 of 70
Elk Grove, CA 875 134 $7,000 23 66.2% 43.1% 8 of 17

The 10th-percentile column is the finished share of the firm one-tenth of the way up from the bottom, among plumbing firms with 10 or more permits in that city. Elk Grove's category includes sewer work.

1. "You don't need a permit for this." For a water heater, a gas line or a sewer line you almost always do; the tankless vs tank guide shows water-heater permits filed in 11 cities. The FTC also lists a contractor who asks you to get the permit yourself as a scam sign (FTC, read October 2026). The portal should show the plumber, not you, as contractor.

2. Its finished share is below its city's 10th percentile. That line is 73.0% in Cincinnati and 36.5% in Cleveland, where 41 of 70 plumbing firms with 10 or more permits finish under 70%. Cities record finals differently, so compare a plumber only with its own city.

3. Its permits take far longer than the city's usual. The usual plumbing permit closes in 23 days in Elk Grove and 234 in Cleveland. A plumber whose own jobs sit open for many times the local usual is leaving gas or drain work uninspected.

4. The quote is far outside what the city's plumbers file. In Arlington the middle half of plumbing firms have a usual filed value between $1,650 and $6,800; in Miami, $3,000 to $9,000. A repipe is not a toilet swap, so compare like with like.

5. No license number, or a lapsed one. In Elk Grove, 89.6% of plumbing firms on permits matched an active CSLB license; 5 matched one that is no longer active. In Cape Coral, 1 firm with 5 or more permits filed none in the last 12 months; in Cleveland, 27.

See every Cincinnati plumber by permit record →

What a clean record does not prove

A final inspection checks code, not workmanship the inspector cannot see, the brand of fixture you were promised, or how the firm handles a leak a month later. Many small plumbing jobs (a faucet, a clog) never need a permit, so a plumber who does mostly service calls can have a thin record and still be good. Insurance and workers' compensation are not on the permit: ask for a certificate naming you and phone the insurer. Cleveland and Cincinnati firms carry no license match here; check OCILB yourself. Our copy updates about monthly; the city portal is the live record.

How we know this

Counts, usual filed values and days to final come from each city's plumbing permits over its three-year window (Cape Coral from January 2025; the others October 2023 to September 2026). "Reached final" is the share of permits a year or more old that the city closed with a final; days to final is the median from issue to final. The 10th-percentile and under-70% columns use plumbing firms with 10 or more permits; the filed-value range uses firms with 3 or more. License status is matched by name to CSLB (Elk Grove) and DBPR (Miami, Cape Coral); Cincinnati and Cleveland have no license match. State rules are quoted from the boards and statutes under Sources and our state guides, read 20 October 2026.

Numbers come from City of Miami building permits (since 2014); City of Cape Coral building permits (the city's open permit table starts January 2025); Arlington County, VA building and trade permits; City of Cincinnati building permits (residential, Residential Code of Ohio); City of Cleveland building permits; City of Elk Grove TRAKiT building permits on single-family, duplex, mobile-home and ADU homes, data through October 17, 2026. Nobody paid to be on this page and nobody can.

Questions

  • Does a plumber need a license?

    Yes, in every state on this page, though not always by the contractor board: Illinois plumbers are licensed by the Department of Public Health, and in Ohio the state license is required for house work through Cleveland's and Cincinnati's contractor registration. Several states require a master plumber behind the firm: Minnesota, Colorado (only a licensee may advertise as a master plumber) and Texas (a Responsible Master Plumber).

  • Can a handyman replace a water heater?

    Usually not legally. Nevada's handyman exemption excludes plumbing at any price, and Arizona's under-$1,000 exemption does not cover a job like a gas water heater. Our plumber vs handyman guide has the rule by state.

  • What finished share is normal for a plumber?

    It depends on the city. 90.8% of Miami plumbing permits a year or more old reached a final, against 58.6% in Cleveland. Among Cincinnati plumbing firms with 10 or more permits, the 10th-percentile firm finished 73.0%; in Cleveland, 36.5%.

  • How much does a plumbing permit job usually cost?

    The usual filed value of a plumbing permit was $3,500 in Cincinnati, $3,000 in Arlington, $4,900 in Miami and $7,000 in Elk Grove (where sewer work is filed with plumbing). Filed values are what the plumber told the city, not the invoice.

  • Does a general contractor's license cover the plumbing on my remodel?

    Often not. In Hawaii the Supreme Court held a general contractor without the C-37 plumbing class could not do the plumbing on its own project; in Texas, Virginia, Massachusetts and New York City the plumber holds its own license. Ask for the plumber's number separately.

Build your own list

Every firm with that kind of permit on record. Pick what you value. The list moves.

Miami plumbing & gasCape Coral plumbing & gasArlington, VA plumbingCincinnati plumbingCleveland plumbingElk Grove plumbing & sewer

Related guides

For one city

All guides →

Sources
  1. Licensing Classifications — CSLB (accessed 2026-10-20)
  2. Check a License — CSLB (accessed 2026-10-20)
  3. California Business and Professions Code § 7159.5 (2025 edition, via Justia) (accessed 2026-10-20)
  4. Contractor Search — Arizona Registrar of Contractors (accessed 2026-10-20)
  5. A.R.S. 32-1121 Persons not required to be licensed (Arizona) (accessed 2026-10-20)
  6. Verify a License — Colorado DORA (accessed 2026-10-20)
  7. Verify a License — Florida DBPR (accessed 2026-10-20)
  8. PVL public license search — Hawaii DCCA (accessed 2026-10-20)
  9. HRS 444-9 (case note, 97 H. 450) (accessed 2026-10-20)
  10. PMSB public search — Iowa Plumbing & Mechanical Systems Board (accessed 2026-10-20)
  11. Licensed Trade Contractors — City of Chicago (accessed 2026-10-20)
  12. eLIPSE occupational license search — Massachusetts (accessed 2026-10-20)
  13. Plumbing contractor licensing basics — Minnesota DLI (accessed 2026-10-20)
  14. License and registration lookup (iMS) — Minnesota DLI (accessed 2026-10-20)
  15. Consumer Awareness — NC State Board of Examiners of Plumbing, Heating & Fire Sprinkler Contractors (accessed 2026-10-20)
  16. License search — NC Plumbing, Heating & Fire Sprinkler board (accessed 2026-10-20)
  17. License Search — Nevada State Contractors Board (accessed 2026-10-20)
  18. NRS Chapter 624 Contractors (NRS 624.031) (accessed 2026-10-20)
  19. Licensed plumbers look-up — NYC Department of Buildings (accessed 2026-10-20)
  20. OCILB License Lookup — Ohio Department of Commerce (accessed 2026-10-20)
  21. Find A Registered Contractor — City of Cincinnati / CAGIS (accessed 2026-10-20)
  22. License Search — Oregon CCB (accessed 2026-10-20)
  23. License search (plumbing, electrical) — Oregon Building Codes Division (accessed 2026-10-20)
  24. Verify a License — Tennessee Department of Commerce & Insurance (accessed 2026-10-20)
  25. Free Licensee List and Public License Search — Texas State Board of Plumbing Examiners (accessed 2026-10-20)
  26. License Lookup — Virginia DPOR (accessed 2026-10-20)
  27. Register as a Contractor — Washington L&I (accessed 2026-10-20)
  28. Verify a Contractor — Washington L&I (accessed 2026-10-20)
  29. How To Avoid a Home Improvement Scam — FTC Consumer Advice (accessed 2026-10-20)