St Louis Plumber License

St. Louis City and St. Louis County Are Separate Jurisdictions

The most common licensing mistake in the St. Louis metro area is assuming a single license covers both sides. St. Louis City and St. Louis County operate completely independent plumbing boards with different exams, different fee structures, and different continuing education requirements. A trade card from the City does not automatically authorize work in the County, and vice versa.

If you work across both — and most metro-area plumbers eventually do — you need two separate licenses.

St. Louis City

The City's Board of Examiners of Plumbers and Drainlayers administers its own proprietary written and practical exams. No ICC or Prometric — the board writes the test.

Experience thresholds:

• Apprentice to journeyman: 5 years
• Journeyman to master: 5 years

Fees:

• Apprentice registration: $10
• Journeyman card: $30
• Master card: $30

St. Louis City uses its own plumbing code rather than adopting the IPC directly. Candidates studying for the City exam should request the current reference code from the Board of Examiners rather than assuming IPC coverage.

The board also issues drainlayer licenses — a separate credential required under RSMo § 341.170 for sewer work outside the building envelope.

St. Louis County

The County's Department of Transportation and Public Works manages licensing through the Accela Citizen Access portal. Exams are administered by IAPMO, not the ICC, and include both written and practical components.

Experience thresholds:

• Apprentice to journeyman: 5 years (board counts 1,500 hours as one year)
• Journeyman to master: 2 years of active journeyman experience

Fees:

• Apprentice registration: $10
• Journeyman local exam/administrative fee: $30, license: $30 (IAPMO testing fees are listed below)
• Master local exam/administrative fee: $30, license: $30 (IAPMO testing fees are listed below)

IAPMO Exam Fee Increases

St. Louis County's testing fees are escalating through January 2027:

Scheduling your exam sooner rather than later saves real money — from July 2026 to January 2027, the increase is $15 for the journeyman in-person exam and $50 for the master in-person exam.

Apprentice Supervision Ratios

St. Louis County enforces strict apprentice density limits. The total number of apprentices cannot exceed the total number of licensed journeymen plus master plumbers employed by the firm. During labor shortages, masters can apply for a temporary waiver allowing up to two additional apprentices, contingent on quarterly manpower reports.

Continuing Education (PEUs)

Master and journeyman plumbers must complete 12 Professional Education Units (24 hours of instruction) every three-year license cycle. At least 3 PEUs must cover St. Louis County plumbing code specifically. Up to 4 PEUs can carry over to the next cycle, but carryovers cannot satisfy the core curriculum requirement.

Providers include Ranken Technical College, Atlas Supply Company (which offers free PEU classes periodically), and various online safety training platforms.

Contractor Setup

For St. Louis County contractors:

• General liability minimum: $500,000 per occurrence
• Surety bond: $10,000 corporate surety bond
• Business entity registered with the Secretary of State

For both City and County, the designated master plumber must be a full-time employee or owner of the contracting business.

Working Both Jurisdictions

Plumbers who hold licenses in both the City and County should track continuing education carefully — the County's PEU requirements are formal and structured, while the City's renewal process operates differently. The Missouri Plumber License Guide maps both jurisdictions side by side and includes a PEU tracker designed for multi-license holders.

See more Missouri guides →