Plumber licensing laws are created by primarily for the protection of the public.

Here is a list of laws related to plumbers, plumbing contractor licensing:

FEDERAL LAWS

• Federal Trade Commission (FTC) - Advertising FAQs

ARKANSAS

• AR - RULES AND REGULATIONS PERTAINING TO PLUMBERS LICENSE FEE, EXPIRATION, RENEWAL, JOURNEYMAN, AND MASTER PLUMBER QUALIFICATIONS

CALIFORNIA

•      CA - Business and Professional Code

COLORADO

• CO - EXAMINING BOARD OF PLUMBERS RULES AND REGULATIONS 3 CCR 720-1

ILLINOIS - Effective legislation - prevents advertising by non-plumbers - effective monetary penalties for violations - can disconnect phone numbers used in illegal ads

• IL - PROFESSIONS AND OCCUPATIONS (225 ILCS 320/) License Law.
• IL - Administrative Code | SECTION 750.1000 CIVIL PENALTIES FOR UNLICENSED PLUMBERS
• IL - Dept. of Public Heath Plumbing license and rules

MAINE

• MA - STATE OF MAINE PLUMBERS’ EXAMINING BOARD LAWS AND RULES

MARYLAND

• MD - Business Regulation - Licenses

MICHIGAN

• MI - State Plumbing Act

NEW HAMPSHIRE

• NH - Revised Statutes Annotated (RSA)

NEW JERSEY

• NJ - State Board of Examiners of Master Plumbers Laws

NEW YORK

• NY - New Yprk City increases fines for unlicensed plumbers

OKLAHOMA

• Oklahoma Plumber Laws

OREGON

• OR - 2008 Oregon Plumbing Specialty Code

PENNSYLVANIA

SB 747

INDIANA

• IN - Indiana Plumbing Commission
• Indiana Plumber Licenses website

TEXAS

• The Texas State Board of Plumbing Examiners

WASHINGTON - Summary: License enforcement is ineffective due to licensing laws allowing anybody to register as a plumbing contractor with no experience requirements. There is a requirement that all plumbing work be done by a licensed plumber but their is no way to find an unlicenced plumber working under cover of a contractor registration. Washington needs a simple change in the law that states: "Only a licensed specialty plumbing  contractor may advertise plumbing services to the public AND only licensed plumbers may register as a  specialy plumbing contracter"

• WA - Revised Commercial Code 18.106 RCW
• WA - WAC 296-200A-016 Definitions
• WA - False Advertising Law RCW 9.04.010

WISCONSIN

• WI - Plumber Creditial Requirments
• WI - Out of state companies must register to do business

Consumer Protection laws | False advertising - http://wilawlibrary.gov/topics/consumer/ads.php