Birdray

CSLB classification · HVAC

C-4 Boiler, Hot Water Heating and Steam Fitting Contractor

Installs and services boilers, hot-water heating and steam systems.

683
Active licences
563
With workers' comp
82%
181
Renewing in 90 days
13
Lapsed or suspended
105
Exempt
5
New in 90 days

Coverages a producer should expect

  • ›Workers' comp
  • ›General liability
  • ›Equipment breakdown for installed systems

WCIRB classes usually assigned

  • 5183 Plumbing

Governing class depends on actual operations and payroll. Verify with the WCIRB classification search before quoting.

Carriers writing this class

Policies on file, statewide

  1. State Compensation Insurance Fund75
  2. Insurance Co. Of The West42
  3. Zurich American Insurance Co.41
  4. Travelers Property Casualty Co. Of America39
  5. Hartford Casualty Insurance Co.19
  6. Everest Premier Insurance Co.17
  7. Employers Preferred Insurance Co.16
  8. Security National Insurance Co.16
  9. Old Republic Insurance Co.15
  10. Amtrust Insurance Co.15

C-4 workers' comp renewals by month, California

22
Sep
114
Oct
34
Nov
27
Dec
76
Jan
27
Feb
37
Mar
65
Apr
32
May
35
Jun
47
Jul
24
Aug
2
Sep

Counties with the most

  1. Los Angeles County91
  2. County50
  3. Alameda County45
  4. San Francisco County42
  5. San Diego County41
  6. Orange County40
  7. Sonoma County36
  8. Contra Costa County35
  9. Santa Clara County32
  10. San Mateo County26
  11. Sacramento County23
  12. Riverside County18

Related classes in HVAC

C-20 Warm-Air Heating, Ventilating and Air-Conditioning ContractorC-38 Refrigeration ContractorD-62 Air and Water Balancing

Frequently asked

What does a C-4 licence allow a contractor to do?
Installs and services boilers, hot-water heating and steam systems.
What insurance does a C-4 contractor need?
Workers' compensation is required by law once they have employees; the CSLB suspends a licence without it. Beyond that, producers usually place: Workers' comp; General liability; Equipment breakdown for installed systems.
How many C-4 contractors are there in California?
683 active licences hold the C-4 classification as of 2026-09-06; 563 (82%) have workers' comp on file and 105 are exempt.
When do C-4 workers' comp policies renew?
181 renew within 90 days. October is the peak month.
Which WCIRB class codes apply to C-4 work?
Most often 5183 (Plumbing). The WCIRB assigns the class from the actual operations and payroll, so verify per account in the WCIRB classification search.
Selling to C-4 contractors in California?
Birdray runs signal-timed outbound for one agency per territory: the companies behind these numbers, the person to email, and the renewal date, sent from your inbox. The database is free to search.
How the outbound worksSearch free

Sources: CSLB licence and workers' compensation records, California Secretary of State, OSHA, FMCSA, county permits. Aggregates only; no individual contractor appears on this page. "Active" means a CLEAR licence status. Renewal counts include policies on file with the CSLB expiring in the window. Refreshed weekly; this page as of 2026-09-06. Every field and its source →

C-4 Boiler, Hot Water Heating and Steam Fitting Contractor: Insurance and WCIRB Classes | Birdray